The Sea Shore
by William S. Furneaux · English · Gutenberg #42978 · 933,814 chars · public domain (US)
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Title: The Sea Shore
Author: William S. Furneaux
Illustrator: R. Lillie
Release date: June 18, 2013 [eBook #42978]
Most recently updated: October 23, 2024
Language: English
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Transcriber’s Note
Due to limitations of this format, some typographical features are not
possible. Italic and bold text is represented in this text as _italic_
and =bold=. Finally, the few superscripted characters are given
in-line, e.g. 'Ltd' or 'A1'.
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The approximate positions of each, including any caption text, is shown
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corrections made, and for any other observations about the text.
THE SEA SHORE
+--------------------------------------------------------------+
| THE OUT-DOOR WORLD SERIES. |
| |
| THE OUT-DOOR WORLD; or, the Young Collector's Handbook. |
| By W. S. FURNEAUX. With 18 Plates (16 of which are |
| Coloured), and 549 Illustrations in the Text. Crown |
| 8vo, 6s. 6d. net. |
| |
| FIELD AND WOODLAND PLANTS. |
| By W. S. FURNEAUX. With 8 Plates in Colour, and numerous |
| other Illustrations by PATTEN WILSON, and from |
| Photographs. Crown 8vo, 6s. 6d. net. |
| |
| BRITISH BUTTERFLIES AND MOTHS. |
| By W. S. FURNEAUX. With 12 Coloured Plates and 241 |
| Illustrations in the Text. Crown 8vo, 6s. 6d. net. |
| |
| LIFE IN PONDS AND STREAMS. |
| By W. S. FURNEAUX. With 8 Coloured Plates and 331 |
| Illustrations in the Text. Crown 8vo, 6s. 6d. net. |
| |
| THE SEA SHORE. By W. S. FURNEAUX. |
| With 8 Coloured Plates and over 300 Illustrations in the |
| Text. Crown 8vo, 6s. 6d. net. |
| |
| BRITISH BIRDS. By W. H. HUDSON. |
| With a Chapter on Structure and Classification by FRANK E. |
| BEDDARD, F.R.S. With 16 Plates (8 of which are Coloured), |
| and 103 Illustrations in the Text. Crown 8vo, 6s. 6d. net. |
| |
| LONGMANS, GREEN & CO., 39 Paternoster Row, London, E.C.4 |
| New York, Toronto, Bombay, Calcutta and Madras. |
+--------------------------------------------------------------+
[Illustration: Plate I, A ROCK-POOL]
THE SEA SHORE
BY
W. S. FURNEAUX
AUTHOR OF
‘THE OUTDOOR WORLD’ ‘BRITISH BUTTERFLIES AND MOTHS’
‘LIFE IN PONDS AND STREAMS’ ETC.
[Illustration]
_WITH EIGHT PLATES IN COLOUR_
_AND OVER THREE HUNDRED ILLUSTRATIONS IN THE TEXT_
_NEW IMPRESSION_
LONGMANS, GREEN AND CO.
39 PATERNOSTER ROW, LONDON, E.C.4
NEW YORK, TORONTO
BOMBAY, CALCUTTA AND MADRAS
1922
All rights reserved
+------------------------------------------------+
| BIBLIOGRAPHICAL NOTE. |
| |
| _First published in September, 1903._ |
| |
| _Re-issue at Cheaper Price, July, 1911._ |
| |
| _New Impression, November, 1922._ |
| |
| |
| _Made in Great Britain_ |
| |
+------------------------------------------------+
PREFACE
To sea-side naturalists it must be a matter of great surprise that of
the inhabitants of our coast towns and villages, and of the
pleasure-seekers that swarm on various parts of the coast during the
holiday season, so few take a real interest in the natural history of
the shore. The tide flows and ebbs and the restless waves incessantly
roll on the beach without arousing a thought as to the nature and cause
of their movements. The beach itself teems with peculiar forms of life
that are scarcely noticed except when they disturb the peace of the
resting visitor. The charming vegetation of the tranquil rock-pool
receives but a passing glance, and the little world of busy creatures
that people it are scarcely observed; while the wonderful forms of life
that inhabit the sheltered nooks of the rugged rocks between the
tide-marks are almost entirely unknown except to the comparatively few
students of Nature. So general is this apparent lack of interest in the
things of the shore that he who delights in the study of littoral life
and scenes but seldom meets with a kindred spirit while following his
pursuits, even though the crowded beach of a popular resort be situated
in the immediate neighbourhood of his hunting ground. The sea-side
cottager is too accustomed to the shore to suppose that he has anything
to learn concerning it, and this familiarity leads, if not to contempt,
most certainly to a disinclination to observe closely; and the visitor
from town often considers himself to be too much in need of his
hard-earned rest to undertake anything that may seem to require energy
of either mind or body.
Let both, however, cast aside any predisposition to look upon the
naturalist’s employment as arduous and toilsome, and make up their minds
to look enquiringly into the living world around them, and they will
soon find that they are led onward from the study of one object to
another, the employment becoming more and more fascinating as they
proceed.
Our aim in writing the following pages is to encourage the observation
of the nature and life of the sea shore; to give such assistance to the
beginner as will show him where the most interesting objects are to be
found, and how he should set to work to obtain them. Practical hints are
also furnished to enable the reader to successfully establish and
maintain a salt-water aquarium for the observation of marine life at
home, and to preserve various marine objects for the purpose of forming
a study-collection of the common objects of the shore.
To have given a detailed description of all such objects would have been
impossible in a work of this size, but a large number have been
described and figured, and the broad principles of the classification of
marine animals and plants have been given such prominence that, it is
hoped, even the younger readers will find but little difficulty in
determining the approximate positions, in the scale of life, of the
various living things that come within their reach.
Of the many illustrations, which must necessarily greatly assist the
reader in understanding the structure of the selected types and in the
identification of the different species, a large number have been
prepared especially for this work.
CONTENTS
CHAPTER PAGE
I. THE GENERAL CHARACTERISTICS OF THE SEA SHORE 1
II. THE SEA-SIDE NATURALIST 21
III. SEA ANGLING 34
IV. THE MARINE AQUARIUM 51
V. THE PRESERVATION OF MARINE OBJECTS 71
VI. EXAMINATION OF MARINE OBJECTS--DISSECTION 91
VII. THE PROTOZOA OF THE SEA SHORE 102
VIII. BRITISH SPONGES 115
IX. THE COELENTERATES--JELLY-FISHES, ANEMONES, AND
THEIR ALLIES 127
X. STARFISHES, SEA URCHINS, ETC. 157
XI. MARINE WORMS 172
XII. MARINE MOLLUSCS 190
XIII. MARINE ARTHROPODS 256
XIV. MARINE VERTEBRATES 306
XV. SEA WEEDS 343
XVI. THE FLOWERING PLANTS OF THE SEA-SIDE 391
INDEX 425
LIST OF COLOURED PLATES
_Drawn by_ MR. ROBERT LILLIE _and reproduced by_
MESSRS. ANDRÉ & SLEIGH, LTD., _Bushey_.
PLATE I--_A ROCK-POOL_ _Frontispiece_
PLATE II--_SEA ANEMONES_ _To face p. 142_
1, 2, 3. _Actinia mesembryanthemum._
4. _Caryophyllia Smithii._
5. _Tealia crassicornis._
6. _Sagartia bellis._
7. _Balanophyllia regia._
8. _Actinoloba dianthus._
PLATE III--_SEA ANEMONES_ _To face p. 150_
1. _Sagartia troglodytes._
2. ” _venusta._
3. _Actinia glauca._
4. ” _chiococca._
5. _Bunodes Ballii._
6. ” _gemmacea._
7. _Anthea cereus._
8. _Sagartia rosea._
PLATE IV--_ECHINODERMS_ _To face p. 168_
1. _Asterias rubens._
2. _Goniaster equestris._
3. _Ophiothrix fragilis._
4. _Echinocardium cordatum._
5. _Echinus miliaris._
6. ” _esculentus._
PLATE V--_MOLLUSCS_ _To face p. 222_
1. _Solen ensis._
2. _Trivia europæa._
3. _Trochus umbilicatus._
4. ” _magnus._
5. _Littorina littorea._
6. ” _rudis._
7. _Haminea_ (_Bulla_) _hydatis_.
8. _Tellina._
9. _Capulus_ (_Pileopsis_) _hungaricus_.
10. _Chrysodomus_ (_Fusus_) _antiquus_.
11. _Buccinum undatum._
12, 13. _Scalaria communis._
14. _Pecten opercularis._
15. " _varius._
16. " _maximus._
PLATE VI--_CRUSTACEA._ _To face p. 290_
1. _Gonoplax angulata._
2. _Xantho florida._
3. _Portunus puber._
4. _Polybius Henslowii._
5. _Porcellana platycheles._
PLATE VII--_SEAWEEDS_ _To face p. 354_
1. _Fucus nodosus._
2. _Nitophyllum laceratum._
3. _Codium tomentosum._
4. _Padina pavonia._
5. _Porphyra laciniata_ (_vulgaris_).
PLATE VIII--_SEAWEEDS_ _To face p. 384_
1. _Chorda filum._
2. _Fucus vesiculosus._
3. ” _canaliculatus._
4. _Delesseria (_Maugeria_) sanguinea_.
5. _Rhodymenia palmata._
6. _Chondrus crispus._
7. _Ulva lactuca._
OTHER ILLUSTRATIONS
FIG. PAGE
1. CHALK CLIFF 3
2. WHITECLIFF (CHALK), DORSET 4
3. PENLEE POINT, CORNWALL 5
4. BALANUS SHELLS 6
5. A CLUSTER OF MUSSELS 7
6. BREAKERS 8
7. ILLUSTRATING THE TIDE-PRODUCING INFLUENCE OF THE MOON 10
8. ILLUSTRATING THE TIDES 11
9. SPRING TIDES AT FULL MOON 12
10. SPRING TIDES AT NEW MOON 12
11. NEAP TIDES 13
12. CHART SHOWING THE RELATIVE TIMES OF HIGH TIDE ON DIFFERENT
PARTS OF THE BRITISH COAST 16
13. THE VASCULUM 22
14. WIRE RING FOR NET 24
15. NET FRAME WITH CURVED POINT 24
16. RHOMBOIDAL FRAME FOR NET 24
17. RHOMBOIDAL NET 25
18. SEMICIRCULAR NET 25
19. THE DREDGE 25
20. THE CRAB-POT 26
21. AN OLD BIRD-CAGE USED AS A CRAB-POT 27
22. A YOUNG NATURALIST AT WORK 32
23. A GOOD HUNTING-GROUND ON THE CORNISH COAST 33
24. ROUND BEND HOOK WITH FLATTENED END 37
25. LIMERICK HOOK, EYED 37
26. METHOD OF ATTACHING SNOOD TO FLATTENED HOOK 38
27. METHOD OF ATTACHING SNOOD TO EYED HOOK 38
28. THE LUGWORM 39
29. THE RAGWORM 40
30. DIGGING FOR BAIT 41
31. METHOD OF OPENING A MUSSEL 42
32. FISHING FROM THE ROCKS 46
33. THE PATERNOSTER 48
34. SECTION OF AN AQUARIUM CONSTRUCTED WITH A MIXTURE OF
CEMENT AND SAND 54
35. CEMENT AQUARIUM WITH A GLASS PLATE IN FRONT 55
36. AQUARIUM OF WOOD WITH GLASS FRONT 56
37. HEXAGONAL AQUARIUM CONSTRUCTED OF ANGLE ZINC, WITH
GLASS SIDES 57
38. METHOD OF AERATING THE WATER OF AN AQUARIUM 65
39. AQUARIUM FITTED WITH APPARATUS FOR PERIODIC
OUTFLOW 67
40. JARS FOR PRESERVING ANATOMICAL AND BIOLOGICAL SPECIMENS 76
41. SHOWING THE DIFFERENT STAGES IN THE MAKING OF A SMALL
SPECIMEN TUBE 77
42. SMALL SPECIMEN TUBE MOUNTED ON A CARD 78
43. SMALL CRAB MOUNTED ON A CARD 82
44. SPRING FOR HOLDING TOGETHER SMALL BIVALVE SHELLS 84
45. THE TRIPLET MAGNIFIER 92
46. A SMALL DISSECTING TROUGH 93
47. CELL FOR SMALL LIVING OBJECTS 95
48. SHEET OF CORK ON THIN SHEET LEAD 99
49. WEIGHTED CORK FOR DISSECTING TROUGH 99
50. THE AMOEBA, HIGHLY MAGNIFIED 102
51. " " SHOWING CHANGES OF FORM 103
52. " " FEEDING 103
53. " " DIVIDING 104
54. A GROUP OF FORAMINIFERS, MAGNIFIED 105
55. A SPIRAL FORAMINIFER SHELL 106
56. A FORAMINIFER OUT OF ITS SHELL 106
57. THE SAME FORAMINIFER (FIG. 56) AS SEEN WHEN ALIVE 107
58. SECTION OF THE SHELL OF A COMPOUND FORAMINIFER 107
59. SECTION OF A NUMMULITE SHELL 108
60. _Globigerina bulloides_, AS SEEN WHEN ALIVE, MAGNIFIED 108
61. SECTION OF A PIECE OF NUMMULITIC LIMESTONE 109
62. A GROUP OF RADIOLARIAN SHELLS, MAGNIFIED 111
63. THREE INFUSORIANS, MAGNIFIED 113
64. A PHOSPHORESCENT MARINE INFUSORIAN (_Noctiluca_),
MAGNIFIED 114
65. SECTION OF A SIMPLE SPONGE 116
66. DIAGRAMMATIC SECTION OF A PORTION OF A COMPLEX SPONGE 117
67. HORNY NETWORK OF A SPONGE, MAGNIFIED 118
68. _Grantia compressa_ 120
69. SPICULES OF _Grantia_, MAGNIFIED 120
70. _Sycon ciliatum_ 121
71. _Leucosolenia botryoides_, WITH PORTION MAGNIFIED 121
72. _Chalina oculata_ 122
73. _Halichondria panicea_ 123
74. SPICULES OF _Halichondria_, MAGNIFIED 124
75. AN OYSTER SHELL, BORED BY _Cliona_ 124
76. SPICULES OF _Cliona_ 125
77. THREAD CELLS OF A COELENTERATE, MAGNIFIED 127
78. THE SQUIRREL'S-TAIL SEA FIR (_Sertularia argentea_),
WITH A PORTION ENLARGED 128
79. _Sertularia filicula_ 129
80. " _cupressina_ 130
81. THE HERRING-BONE POLYPE (_Halecium halecinum_) 131
82. _Tubularia indivisa_ 132
83. THE BOTTLE BRUSH (_Thuiaria thuja_) 132
84. _Antennularia antennia_ 133
85. _Aurelia aurita_ 135
86. THE EARLY STAGES OF _Aurelia_ 136
87. _Rhizostoma_ 136
88. _Chrysaora_ 136
89. _Cydippe pileus_ 137
90. SECTION OF AN ANEMONE 139
91. STINGING CELLS OF ANEMONE, HIGHLY MAGNIFIED 140
92. DIAGRAMMATIC TRANSVERSE SECTION OF AN ANEMONE 140
93. LARVA OF ANEMONE 140
94. THE TRUMPET ANEMONE (_Aiptasia Couchii_), CORNWALL;
DEEP WATER 144
95. _Peachia hastata,_ S. DEVON 145
96. _Sagartia pallida,_ DEVON AND CORNWALL 146
97. _Sagartia nivea,_ DEVON AND CORNWALL 147
98. _Corynactus viridis,_ DEVON AND CORNWALL 148
99. _Bunodes thallia,_ WEST COAST 150
100. _Bunodes gemmacea,_ WITH TENTACLES RETRACTED 151
101. _Caryophyllia cyathus_ 152
102. _Sagartia parasitica_ 153
103. THE CLOAK ANEMONE (_Adamsia palliata_) ON A WHELK
SHELL, WITH HERMIT CRAB 154
104. LARVA OF THE BRITTLE STARFISH 158
105. LARVA OF THE FEATHER STAR 160
106. THE ROSY FEATHER STAR 160
107. THE COMMON BRITTLE STAR 162
108. SECTION OF THE SPINE OF A SEA URCHIN 165
109. SEA URCHIN WITH SPINES REMOVED ON ONE SIDE 166
110. APEX OF SHELL OF SEA URCHIN 166
111. SHELL OF SEA URCHIN WITH TEETH PROTRUDING 167
112. INTERIOR OF SHELL OF SEA URCHIN 167
113. MASTICATORY APPARATUS OF SEA URCHIN 167
114. SEA URCHIN DISSECTED, SHOWING THE DIGESTIVE TUBE 168
115. THE SEA CUCUMBER 170
116. A TURBELLARIAN, MAGNIFIED 175
117. _Arenicola piscatorum_ 178
118. THE SEA MOUSE 179
119. TUBE-BUILDING WORMS: _Terebella, Serpula, Sabella_ 182
120. _Terebella_ REMOVED FROM ITS TUBE 183
121. A TUBE OF _Serpula_ ATTACHED TO A SHELL 185
122. _Serpula_ REMOVED FROM ITS TUBE 186
123. THE SEA MAT (_Flustra_) 187
124. _Flustra_ IN ITS CELL, MAGNIFIED 188
125. SEA SQUIRT 189
126. LARVÆ OF MOLLUSCS 191
127. SHELL OF THE PRICKLY COCKLE (_Cardium aculeatum_)
SHOWING UMBO AND HINGE; ALSO THE INTERIOR
SHOWING THE TEETH 192
128. INTERIOR OF BIVALVE SHELL, SHOWING MUSCULAR SCARS
AND PALLIAL LINE 193
129. DIAGRAM OF THE ANATOMY OF A LAMELLIBRANCH 194
130. _Mytilus edulis_, WITH BYSSUS 195
131. A BIVALVE SHELL (_Tapes virgineana_) 196
132. _Pholas dactylus_ 199
133. " " INTERIOR OF VALVE; AND _Pholadidea_
WITH ANIMAL 201
134. THE SHIP WORM 202
135. 1. _Teredo navalis._ 2. _Teredo norvegica_ 202
136. _Gastrochæna modiolina_ 203
137. 1. _Thracia phaseolina._ 2. _Thracia pubescens_,
SHOWING PALLIALLINE 204
138. 1. _Mya truncata._ 2. INTERIOR OF SHELL.
3. _Mya arenaria._4. _Corbula nucleus_ 205
139. _Solen siliqua_ 206
140. 1. _Solen ensis._ 2. _Cerati-solen legumen._
3. _Solecurtus candidus_ 207
141. _Tellinidæ_ 208
142. 1. _Lutraria elliptica._ 2. PART OF THE HINGE OF
_Lutraria_, SHOWING THE CARTILAGE PIT. 3. _Macra
stultorum._ 4. INTERIOR OF SAME SHOWING PALLIAL
LINE 210
143. _Veneridæ_ 211
144. _Cyprinidæ_ 213
145. _Galeomma Turtoni_ 214
146. 1. _Cardium pygmæum._ 2. _Cardium fasciatum._
3. _Cardium rusticum_ 215
147. _Cardium aculeatum_ 215
148. _Pectunculus glycimeris_, WITH PORTION OF VALVE
SHOWING TEETH, AND _Arca tetragona_ 216
149. _Mytilus edulis_ 217
150. 1. _Modiola modiolus._ 2. _Modiola tulipa._
3. _Crenella discors_ 218
151. _Dreissena polymorpha_ 219
152. _Avicula_, AND _Pinna pectinata_ 220
153. 1. _Anomia ephippium._ 2. _Pecten tigris._
3. _Pecten_, ANIMAL IN SHELL 222
154. _Terebratulina._ THE UPPER FIGURE REPRESENTS THE
INTERIOR OF THE DORSAL VALVE 224
155. UNDER SIDE OF THE SHELL OF _Natica catena_, SHOWING
THE UMBILICUS; AND OUTLINE OF THE SHELL, SHOWING THE
RIGHT-HANDED SPIRAL 225
156. SECTION OF THE SHELL OF THE WHELK, SHOWING THE
COLUMELLA 226
157. DIAGRAM OF THE ANATOMY OF THE WHELK, THE SHELL BEING
REMOVED 228
158. A PORTION OF THE LINGUAL RIBBON OF THE WHELK,
MAGNIFIED; AND A SINGLE ROW OF TEETH ON A MUCH
LARGER SCALE 229
159. EGG CASES OF THE WHELK 230
160. PTEROPODS 231
161. NUDIBRANCHS 234
162. " 235
163. SHELLS OF TECTIBRANCHS 236
164. CHITON SHELLS 238
165. SHELLS OF _Dentalium_ 238
166. _Patellidæ_ 239
167. _Calyptræa sinensis_ 241
168. _Fissurellidæ_ 241
169. _Haliotis_ 242
170. _Ianthina fragilis_ 242
171. _Trochus zizyphinus_. 2. UNDER SIDE OF SHELL.
3. _Trochus magnus._ 4. _Adeorbis subcarinatus_ 244
172. _Rissoa labiosa_ AND _Lacuna pallidula_ 244
173. SECTION OF SHELL OF _Turritella_ 245
174. _Turritella communis_ AND _Cæcum trachea_ 245
175. _Cerithium reticulatum_ AND _Aporrhais pes-pelicani_ 245
176. _Aporrhais pes-pelicani_, SHOWING BOTH SHELL AND ANIMAL 246
177. 1. _Odostomia plicata._ 2. _Eulima polita._
3. _Aclis supranitida_ 246
178. _Cypræa_ (_Trivia_) _europæa_ 247
179. 1. _Ovulum patulum_. 2. _Erato lævis_ 248
180. _Mangelia septangularis_ AND _Mangelia turricula_ 248
181. 1. _Purpura lapillus._ 2. EGG CASES OF _Purpura_.
3. _Nassa reticulata_ 249
182. _Murex erinaceus_ 249
183. OCTOPUS 251
184. _Loligo vulgaris_ AND ITS PEN 252
185. _Sepiola atlantica_ 252
186. _Sepia officinalis_ AND ITS 'BONE' 253
187. EGGS OF _Sepia_ 254
188. THE NERVE-CHAIN OF AN ARTHROPOD (LOBSTER) 257
189. SECTION THROUGH THE COMPOUND EYE OF AN ARTHROPOD 260
190. FOUR STAGES IN THE DEVELOPMENT OF THE COMMON SHORE
CRAB 261
191. THE BARNACLE 261
192. FOUR STAGES IN THE DEVELOPMENT OF THE ACORN BARNACLE 262
193. A CLUSTER OF ACORN SHELLS 263
194. SHELL OF ACORN BARNACLE (_Balanus_) 263
195. THE ACORN BARNACLE (_Balanus porcatus_) WITH APPENDAGES
PROTRUDED 264
196. A GROUP OF MARINE COPEPODS, MAGNIFIED 265
197. A GROUP OF OSTRACODE SHELLS 265
198. _Evadne_ 266
199. MARINE ISOPODS 267
200. MARINE AMPHIPODS 268
201. THE MANTIS SHRIMP (_Squilla Mantis_) 270
202. THE OPOSSUM SHRIMP (_Mysis chamæleon_) 271
203. PARTS OF LOBSTER'S SHELL, SEPARATED, AND VIEWED FROM
ABOVE 272
204. A SEGMENT OF THE ABDOMEN OF A LOBSTER 272
205. APPENDAGES OF A LOBSTER 273
206. LONGITUDINAL SECTION OF THE LOBSTER 274
207. THE SPINY LOBSTER (_Palinurus vulgaris_) 275
208. THE NORWAY LOBSTER (_Nephrops norvegicus_) 276
209. 1. THE MUD-BORER (_Gebia stellata_). 2. THE
MUD-BORROWER (_Callianassa subterranea_) 277
210. THE COMMON SHRIMP (_Crangon vulgaris_) 278
211. THE PRAWN (_Palæmon serratus_) 279
212. _Dromia vulgaris_ 282
213. THE HERMIT CRAB IN A WHELK SHELL 282
214. THE LONG-ARMED CRAB (_Corystes Cassivelaunus_) 287
215. SPIDER CRABS AT HOME 288
216. THE THORNBACK CRAB (_Maia Squinado_) 290
217. THE PEA CRAB (_Pinnotheres pisum_) 290
218. THE COMMON SHORE CRAB (_Carcinus mænas_) 291
219. THE SHORE SPIDER 294
220. THE LEG OF AN INSECT 295
221. TRACHEA OF AN INSECT, MAGNIFIED 296
222. SEA-SHORE INSECTS 298
223. MARINE BEETLES OF THE GENUS _Bembidium_ 302
224. MARINE BEETLES 303
225. TRANSVERSE SECTION THROUGH THE BONY FRAMEWORK OF A
TYPICAL VERTEBRATE ANIMAL 306
226. THE SEA LAMPREY 309
227. THE PILCHARD 310
228. THE SKELETON OF A FISH (PERCH) 315
229. THE INTERNAL ORGANS OF THE HERRING 316
230. THE EGG-CASE OF THE DOGFISH 319
231. THE SMOOTH HOUND 320
232. THE COMMON EEL 323
233. THE LESSER SAND EEL 326
234. THE THREE-BEARDED ROCKLING 327
235. THE SNAKE PIPE-FISH 328
236. THE RAINBOW WRASS (_Labrus julis_) 330
237. THE CORNISH SUCKER 330
238. THE FIFTEEN-SPINED STICKLEBACK AND NEST 331
239. THE SMOOTH BLENNY 333
240. THE BUTTERFISH 334
241. THE BLACK GOBY 335
242. THE FATHER LASHER 335
243. THE LESSER WEAVER 337
244. THE COMMON PORPOISE 341
245. _Callithamnion roseum_ 359
246. _Callithamnion tetricum_ 359
247. _Griffithsia corallina_ 361
248. _Halurus equisetifolius_ 361
249. _Pilota plumosa_ 361
250. _Ceramium diaphanum_ 363
251. _Plocamium_ 366
252. _Delesseria alata_ 368
253. _Delesseria hypoglossum_ 368
254. _Laurencia pinnatifida_ 371
255. _Laurencia obtusa_ 371
256. _Polysiphonia fastigiata_ 373
257. _Polysiphonia parasitica_ 374
258. _Polysiphonia Brodiæi_ 374
259. _Polysiphonia nigrescens_ 374
260. _Ectocarpus granulosus_ 378
261. _Ectocarpus siliculosus_ 378
262. _Ectocarpus Mertensii_ 378
263. _Sphacelaria cirrhosa_ 379
264. _Sphacelaria plumosa_ 379
265. _Sphacelaria radicans_ 380
266. _Cladostephus spongiosus_ 380
267. _Chordaria flagelliformis_ 380
268. _Laminaria bulbosa_ 384
269. _Laminaria saccharina_ 384
270. _Alaria esculenta_ 385
271. _Sporochnus pedunculatus_ 385
272. _Desmarestia ligulata_ 386
273. _Himanthalia lorea_ 387
274. _Cystoseira ericoides_ 388
275. TRANSVERSE SECTION OF THE STEM OF A MONOCOTYLEDON 391
276. LEAF OF A MONOCOTYLEDON 392
277. EXPANDED SPIKELET OF THE OAT 393
278. THE SEA LYME GRASS 395
279. _Knappia agrostidea_ 397
280. THE DOG'S-TOOTH GRASS 397
281. THE REED CANARY GRASS 397
282. MALE AND FEMALE FLOWERS OF _CAREX_, MAGNIFIED 399
283. THE SEA SEDGE 400
284. THE CURVED SEDGE 400
285. THE GREAT SEA RUSH 400
286. THE BROAD-LEAVED GRASS WRACK 401
287. THE SEA-SIDE ARROW GRASS 401
288. THE COMMON ASPARAGUS 401
289. THE SEA SPURGE 403
290. THE PURPLE SPURGE 404
291. THE SEA BUCKTHORN 404
292. _Chenopodium botryoides_ 405
293. THE FROSTED SEA ORACHE 406
294. THE PRICKLY SALT WORT 406
295. THE CREEPING GLASS WORT 407
296. THE SEA-SIDE PLANTAIN 408
297. THE SEA LAVENDER 408
298. THE DWARF CENTAURY 410
299. THE SEA SAMPHIRE 412
300. THE SEA-SIDE EVERLASTING PEA 413
301. THE SEA STORK'S-BILL 414
302. THE SEA CAMPION 416
303. THE SEA PEARL WORT 417
304. THE SHRUBBY MIGNONETTE 417
305. THE WILD CABBAGE 418
306. THE ISLE OF MAN CABBAGE 418
307. THE GREAT SEA STOCK 419
308. THE HOARY SHRUBBY STOCK 419
309. THE SCURVY GRASS 419
310. THE SEA RADISH 419
311. THE SEA ROCKET 420
312. THE SEA KALE 421
313. THE HORNED POPPY 422
THE SEA SHORE
CHAPTER I
_THE GENERAL CHARACTERISTICS OF THE SEA SHORE_
What are the attractions which so often entice us to the sea shore,
which give such charm to a ramble along the cliffs or the beach, and
which will so frequently constrain the most active wanderer to rest and
admire the scene before him? The chief of these attractions is
undoubtedly the incessant motion of the water and the constant change of
scene presented to his view. As we ramble along a beaten track at the
edge of the cliff, new and varied features of the coast are constantly
opening up before us. Each little headland passed reveals a sheltered
picturesque cove or a gentle bay with its line of yellow sands backed by
the cliffs and washed by the foaming waves; while now and again our path
slopes down to a peaceful valley with its cluster of pretty cottages,
and the rippling stream winding its way towards the sea. On the one hand
is the blue sea, full of life and motion as far as the eye can reach,
and on the other the cultivated fields or the wild and rugged downs.
The variety of these scenes is further increased by the frequent changes
in the character of the cliffs themselves. Where they are composed of
soft material we find the coast-line washed into gentle curves, and the
beach formed of a continuous stretch of fine sand; but where harder
rocks exist the scenery is wild and varied, and the beach usually strewn
with irregular masses of all sizes.
Then, when we approach the water’s edge, we find a delight in watching
the approaching waves as they roll over the sandy or pebbly beach, or
embrace an outlying rock, gently raising its olive covering of dangling
weeds.
Such attractions will allure the ordinary lover of Nature--the mere
seeker after the picturesque--but to the true naturalist there are many
others. The latter loves to read in the cliffs their past history, to
observe to what extent the general scenery of the coast is due to the
nature of the rocks, and to learn the action of the waves from the
character of the cliffs and beach, and from the changes which are known
to have taken place in the contour of the land in past years. He also
delights to study those plants and flowers which are peculiar to the
coast, and to observe how the influences of the sea have produced
interesting modifications in certain of our flowering plants, as may be
seen by comparing them with the same species from inland districts. The
sea birds, too, differing so much as they do from our other feathered
friends in structure and habit, provide a new field for study; while the
remarkably varied character of the forms of life met with on the beach
and in the shallow waters fringing the land is in itself sufficient to
supply the most active naturalist with material for prolonged and
constant work.
Let us first observe some of the general features of the coast itself,
and see how far we can account for the great diversity of character
presented to us, and for the continual changes and incessant motions
that add such a charm to the sea-side ramble.
Here we stand on the top of a cliff composed of a soft calcareous
rock--on the exposed edge of a bed of chalk that extends far inland. All
the country round is gently undulating, and devoid of any of the
features that make up a wild and romantic scene. The coast-line, too, is
wrought into a series of gentle bays, separated by inconspicuous
promontories where the rock, being slightly harder, has better withstood
the eroding action of the sea; or where a current, washing the
neighbouring shore, has been by some force deflected seaward. The cliff,
though not high, rises almost perpendicularly from the beach, and
presents to the sea a face which is but little broken, and which in
itself shows no strong evidence of the action of raging, tempestuous
seas; its chief diversity being its gradual rise and fall with each
successive undulation of the land. The same soft and gentle nature
characterises the beach below. Beyond a few small blocks of
freshly-loosened chalk, with here and there a liberated nodule of flint,
we find nothing but a continuous, fine, siliceous sand, the surface of
which is but seldom broken by the protrusion of masses from below. Such
cliffs and beaches do not in themselves suggest any violent action on
the part of the sea, and yet it is here that the ocean is enabled to
make its destructive efforts with the greatest effect. The soft rock is
gradually but surely reduced, partly by the mechanical action of the
waves and partly by the chemical action of the sea-water. The rock
being almost uniformly soft, it is uniformly worn away, thus presenting
a comparatively unbroken face. Its material is gradually dissolved in
the sea; and the calcareous matter being thus removed, we have a beach
composed of the remains of the flints which have been pulverised by the
action of the waves. Thus slowly but surely the sea gains upon the land.
Thus it is that many a famous landmark, once hundreds of yards from the
coast, now stands so near the edge of the cliff as to be threatened by
every storm; or some ancient castle, once miles from the shore, lies
entirely buried by the encroaching sea.
[Illustration: FIG. 1.--CHALK CLIFF]
The coast we have described is most certainly not the one with the
fullest attractions for the naturalist, for the cliffs lack those nooks
that provide so much shelter for bird and beast, and the rugged coves
and rock pools in which we find such a wonderful variety of marine life
are nowhere to be seen. But, although it represents a _typical_ shore
for a chalky district, yet we may find others of a very different nature
even where the same rock exists. Thus, at Flamborough in Yorkshire, and
St. Alban’s Head in Dorset, we find the hardened, exposed edge of the
chalk formation terminating in bold and majestic promontories, while
the inner edge surrounding the Weald gives rise to the famous cliffs of
Dover and the dizzy heights of Beachy Head. The hard chalk of the Isle
of Wight, too, which has so well withstood the repeated attacks of the
Atlantic waves, presents a bold barrier to the sea on the south and east
coasts, and terminates in the west with the majestic stacks of the
Needles.
[Illustration: FIG. 2.--WHITECLIFF (CHALK), DORSET]
Where this harder chalk exists the coast is rugged and irregular. Sea
birds find a home in the sheltered ledges and in the protected nooks of
its serrated edge; and the countless wave-resisting blocks of weathered
chalk that have been hurled from the heights above, together with the
many remnants of former cliffs that have at last succumbed to the
attacks of the boisterous sea, all form abundant shelter for a variety
of marine plants and animals.
[Illustration: FIG. 3.--PENLEE POINT, CORNWALL]
But it is in the west and south-west of our island that we find both
the most furious waves and the rocks that are best able to resist their
attacks. Here we are exposed to the full force of the frontal attacks of
the Atlantic, and it is here that the dashing breakers seek out the
weaker portions of the upturned and contorted strata, eating out deep
inlets, and often loosening enormous blocks of the hardest material,
hurling them on the rugged beach, where they are eventually to be
reduced to small fragments by the continual clashing and grinding action
of the smaller masses as they are thrown up by the angry sea. Here it is
that we find the most rugged and precipitous cliffs, bordering a more or
less wild and desolate country, now broken by a deep and narrow chasm
where the resonant roar of the sea ascends to the dizzy heights above,
and anon stretching seaward into a rocky headland, whose former
greatness is marked by a continuation of fantastic outliers and smaller
wave-worn masses of the harder strata. Here, too, we find that the
unyielding rocks give a permanent attachment to the red and olive weeds
which clothe them, and which provide a home for so many inhabitants of
our shallow waters. It is here, also, that we see those picturesque rock
pools of all sizes, formed by the removal of the softer material of the
rocks, and converted into so many miniature seas by the receding of the
tide.
[Illustration: FIG. 4.--BALANUS SHELLS]
A more lovely sight than the typical rock pool of the West coast one can
hardly imagine. Around lies the rugged but sea-worn rock, partly hidden
by dense patches of the conical shells of the _Balanus_, with here and
there a snug cluster of young mussels held together by their
intertwining silken byssi. The surface is further relieved by the
clinging limpet, the beautifully banded shells of the variable
dog-periwinkle, the pretty top shells, and a variety of other common but
interesting molluscs. Clusters of the common bladdery weeds are also
suspended from the dry rock, and hang gracefully into the still water
below, where the mantled cowry may be seen slowly gliding over the olive
fronds. Submerged in the peaceful pool are beautiful tufts of white and
pink corallines, among which a number of small and slender starfishes
may climb unnoticed by the casual observer; while the scene is
brightened by the numerous patches of slender green and red algæ, the
thread-like fronds of which are occasionally disturbed as the lively
little blenny darts among them to evade the intruder’s glance. Dotted
here and there are the beautiful anemones--the variously-hued animal
flowers of the sea, with expanded tentacles gently and gracefully
swaying, ready to grasp and paralyse any small living being that may
wander within their reach. Here, under a projecting ledge of the rock,
partly hidden by pale green threads, are the glaring eyes of the
voracious bullhead, eager to pounce on almost any moving object; while
above it the five-fingered starfish slowly climbs among the dangling
weeds by means of its innumerable suckers. In yonder shady corner, where
the overhanging rock cuts off all direct rays of the sun from the deeper
water of the pool, are the pink and yellow incrustations of little
sponges, some of the latter colour resembling a group of miniature
inverted volcanic cones, while on the sandy floor of the pool itself may
be seen the transparent phantom-like prawn, with its rapidly moving
spinnerets and gently-waving antennæ, suddenly darting backward when
disturbed by the incautious approach of the observer; and the spotted
sand-crab, entirely buried with the exception of its upper surface, and
so closely imitating its surroundings as to be quite invisible except on
the closest inspection. Finally, the scene is greatly enlivened by the
active movements of the hermit-crab, that appropriates to its own use
the shell which once covered the body of a mollusc, and by the erratic
excursions of its cousin crabs as they climb over the weedy banks of the
pool in search of food.
[Illustration: FIG. 5.--A CLUSTER OF MUSSELS]
Thus we may find much to admire and study on the sea shore at all times,
but there are attractions of quite another nature that call for notice
on a stormy day, especially on the wilder and more desolate western
coasts. At such times we delight to watch the distant waves as they
approach the shore, to see how they become gradually converted into the
foaming breakers that dash against the standing rocks and wash the
rattling pebbles high on the beach. The powerful effects of the sea in
wearing away the cliffs are now apparent, and we can well understand
that even the most obdurate of rocks must sooner or later break away
beneath its mighty waves.
[Illustration: FIG. 6.--BREAKERS]
The extreme mobility of the sea is displayed not only by the storm
waves, and by the soft ripples of the calm day, but is seen in the
gentle currents that almost imperceptibly wash our shores, and more
manifestly in the perpetual motions of the tides.
This last-named phenomenon is one of extreme interest to the sea-side
rambler, and also one of such great importance to the naturalist that we
cannot do better than spend a few moments in trying to understand how
the swaying of the waters of the ocean is brought about, and to see what
determines the period and intensity of its pulsations, as well as some
of the variations in the daily motions which are to be observed on our
own shores.
In doing this we shall, of course, not enter fully into the technical
theories of the tides, for which the reader should refer to
authoritative works on the subject, but merely endeavour to briefly
explain the observed oscillations of the sea and the general laws which
govern them.
The most casual observer must have noticed the close connection between
the movements of the ocean and the position of the moon, while those who
have given closer attention to the subject will have seen that the
relative heights of the tides vary regularly with the relative positions
of the sun, moon, and earth.
In the first place, then, we notice that the time of high tide in any
given place is always the same at the same period of the cycle of the
moon; that is, it is always the same at the time of new moon, full moon,
&c. Hence it becomes evident that the moon is the prime mover in the
formation of tides. Now, it is a fact that the sun, though about
ninety-three millions of miles from the earth, has a much greater
attractive influence on the earth and its oceans than the moon has,
although the distance of the latter is only about a quarter of a million
miles: but this is due to the vastly superior mass of the sun, which is
about twenty-six million times the mass of the moon. How is it, then,
that we find the tides apparently regulated by the moon rather than by
the sun?
The reason is that the tide-producing influence is due not to the actual
attractive force exerted on the earth as a whole, but to the difference
between the attraction for one side of the globe and that for the
opposite side. Now, it will be seen that the diameter of the
earth--about eight thousand miles--is an appreciable fraction of the
moon’s distance, and thus the attractive influence of the moon for the
side of the earth nearest to it will be appreciably greater than that
for the opposite side; while in the case of the sun, the earth’s
diameter is such a small fraction of the distance from the sun that the
_difference_ in the attractive force for the two opposite sides of the
earth is comparatively small.
Omitting, then, for the present the minor tide-producing influence of
the sun, let us see how the incessant rising and falling of the water of
the ocean are brought about; and, to simplify our explanation, we will
imagine the earth to be a globe entirely covered with water of uniform
depth.
The moon attracts the water on the side nearest to it with a greater
force than that exerted on the earth itself; hence the water is caused
to bulge out slightly on that side. Again, since the attractive force of
the moon for the earth as a whole is greater than that for the water on
the opposite side, the earth is pulled away, as it were, from the water
on that side, causing it to bulge out there also. Hence high tides are
produced on two opposite sides of the earth at the same time, while the
level of the water is correspondingly reduced at two other parts at
right angles with these sides.
This being the case, how are we to account for the observed changes in
the level of the sea that occur every day on our shores?
Let us first see the exact nature of these changes:--At a certain time
we find the water high on the beach; and, soon after reaching its
highest limit, a gradual descent takes place, generally extending over a
period of a little more than six hours. This is then followed by another
rise, occupying about the same time, and the oscillations are repeated
indefinitely with remarkable regularity as to time.
[Illustration: FIG. 7.--ILLUSTRATING THE TIDE-PRODUCING INFLUENCE OF
THE MOON]
Now, from what has been previously said with regard to the tidal
influence of the moon, we see that the tide must necessarily be high
under the moon, as well as on the side of the earth directly opposite
this body, and that the high tides must follow the moon in its regular
motion. But we must not forget that the earth itself is continually
turning on its axis, making a complete rotation in about twenty-four
hours; while the moon, which revolves round the earth in about
twenty-eight days, describes only a small portion of its orbit in the
same time; thus, while the tidal wave slowly follows the moon as it
travels in its orbit, the earth slips round, as it were, under the tidal
wave, causing four changes of tide in approximately the period of one
rotation. Suppose, for example, the earth to be performing its daily
rotation in the direction indicated by the arrow (fig. 8), and the tide
high at the place marked A¹, just under the moon, then, in about six
hours, this place will have been carried round to A², where the tide is
low; and, after similar intervals, to A³ and A⁴ successively, where
the tide is high and low respectively. Hence the daily changes are to a
great extent determined by the rotation of the earth.
But we have already observed that each change of tide occupies a little
more than six hours, the average time being nearly six hours and a
quarter, and so we find that the high and low tides occur nearly an hour
later every day. This is due to the fact that, owing to the revolution
of the moon round the earth in the same direction as that of the
rotation of the earth itself, the day as measured by the moon is nearly
an hour longer than the average solar day as given by the clock.
[Illustration: FIG. 8.--ILLUSTRATING THE TIDES]
There is yet another point worth noting with regard to the relation
between the moon and the tidal movements of the water, which is that the
high tides are never exactly under the moon, but always occur some time
after the moon has passed the meridian. This is due to the inertia of
the ocean, and to the resistance offered by the land to its movements.
Now, in addition to these diurnal changes of the tide, there are others,
extending over longer periods, and which must be more or less familiar
to everyone who has spent some time on the coast. On a certain day, for
instance, we observe that the high tide flows very far up the beach, and
that this is followed, a few hours later, by an unusually low ebb,
exposing rocks or sand-banks that are not frequently visible. Careful
observations of the motions of the water for some days after will show
that this great difference between the levels of high and low-water
gradually decreases until, about a week later, it is considerably
reduced, the high tide not flowing so far inland and the low-water mark
not extending so far seaward. Then, from this time, the difference
increases again, till, after about two weeks from the commencement of
our observations, we find it at the maximum again.
[Illustration: FIG. 9.--SPRING TIDES AT FULL MOON]
Here again we find that the changes exactly coincide with changes in the
position of the moon with regard to the sun and the earth. Thus, the
_spring tides_--those which rise very high and fall very low--always
occur when the moon is full or new; while the less vigorous _neap tides_
occur when the moon is in her quarters and presents only one-half of her
illuminated disc to the earth. And, as the moon passes through a
complete cycle of changes from _new_ to _first-quarter_, _full_,
_last-quarter_, and then to _new_ again in about twenty-nine days, so
the tides run through four changes from spring to neap, spring, neap,
and then to spring again in the same period.
[Illustration: FIG. 10.--SPRING TIDES AT NEW MOON]
The reason for this is not far to seek, for we have already seen that
both sun and moon exert a tide-producing influence on the earth, though
that of the moon is considerably greater than that of the sun; hence, if
the sun, earth, and moon are in a straight line, as they are when the
moon is full, at which time she and the sun are on opposite sides of the
earth, and also when new, at which time she is between the earth and
sun, the sun’s tide is added to the moon’s tide, thus producing the
well-marked spring tides; while, when the moon is in her quarters,
occupying a position at right angles from the sun as viewed from the
earth, the two bodies tend to produce high tides on different parts of
the earth at the same time, and thus we have the moon’s greater tides
reduced by the amount of the lesser tides of the sun, with the result
that the difference between high and low tides is much lessened.
[Illustration: FIG. 11.--NEAP TIDES]
Again, the difference between high and low water marks is not always
exactly the same for the same kind of tide--the spring tide for a
certain period, for example, not having the same limits as the same tide
of another time. This is due to the fact that the moon revolves round
the sun in an elliptical orbit, while the earth, at the same time,
revolves round the sun in a similar path, so that the distances of both
moon and sun from the earth vary at different times. And, since the
tide-producing influences of both these bodies must increase as their
distance from the earth diminishes, it follows that there must be
occasional appreciable variations in the vigour of the tidal movements
of the ocean.
As the earth rotates on its axis, while at the same time the tidal wave
must necessarily keep its position under the moon, this wave appears to
sweep round the earth with considerable velocity. The differences in the
level of the ocean thus produced would hardly be appreciable if the
earth were entirely covered with water; but, owing to the very irregular
distribution of the land, the movements of the tidal wave become
exceedingly complex; and, when it breaks an entrance into a gradually
narrowing channel, the water is compressed laterally, and
correspondingly increased in height. It is thus that we find a much
greater difference between the levels of high and low tides in
continental seas than are to be observed on the shores of oceanic
islands.
We have occupied so much of our time and space in explanation of the
movements of the tides not only because we think it desirable that all
who delight in sea-side rambles should understand something of the
varied motions which help to give such a charm to the sea, but also
because, as we shall observe later, these motions are a matter of great
importance to those who are interested in the observation and study of
marine life. And, seeing that we are writing more particularly for the
young naturalists of our own island, we must devote a little space to
the study of the movements of the tidal wave round Great Britain, in
order that we may understand the great diversity in the time of high
tide on any one day on different parts of the coast, and see how the
time of high tide for one part may be calculated from that of any other
locality.
Were it not for the inertia of the ocean and the resistance offered by
the irregular continents, high tide would always exist exactly under the
moon, and we should have high water at any place just at the time when
the moon is in the south and crossing the meridian of that place. But
while the inertia of the water tends to make all tides late, the
irregular distribution of the land breaks up the tidal wave into so many
wave-crests and greatly retards their progress.
Thus, the tidal wave entering the Atlantic round the Cape of Good Hope
mingles with another wave that flows round Cape Horn, and the combined
wave travels northward at the rate of several hundred miles an hour. On
reaching the British Isles it is broken up, one wave-crest travelling up
the English Channel, while another flows round Scotland and then
southwards into the North Sea.
The former branch, taking the shorter course, determines the time of
high tide along the Channel coast. Passing the Land’s End, it reaches
Plymouth in about an hour, Torquay in about an hour and a half, the Isle
of Portland in two hours and a half, Brighton in about seven hours, and
London in about nine hours and a half. The other branch, taking a much
longer course, makes its arrival in the southern part of the North Sea
about twelve hours later, thus mingling at that point with the Channel
wave of the _next_ tide. It takes about twenty hours to travel from the
south-west coast of Ireland, round Scotland, and then to the mouth of
the Thames. Where the two waves meet, the height of the tides is
considerably increased; and it will be understood that, at certain
points, where the rising of one tide coincides with the falling of
another, the two may partially or entirely neutralise each other.
Further, the flow and the ebb of the tide are subject to numerous
variations and complications in places where two distinct tidal
wave-crests arrive at different times. Thus, the ebbing of the tide may
be retarded by the approach of a second crest a few hours after the
first, so that the ebb and the flow do not occupy equal times. At
Eastbourne, for example, the water flows for about five hours, and ebbs
for about seven and a half. Or, the approach of the second wave may even
arrest the ebbing waters, and produce a second high tide during the
course of six hours, as is the case at some places along the Hampshire
and Dorset coasts.
Those who visit various places on our own coasts will probably be
interested in tracing the course of the tidal crests by the aid of the
accompanying map of the British Isles, on which the time of high tide at
several ports for the same time of day is marked. It will be seen from
this that the main tidal wave from the Atlantic approaches our islands
from the south-west, and divides into lesser waves, one of which passes
up the Channel, and another round Scotland and into the North Sea, as
previously mentioned, while minor wave-crests flow northward into the
Irish Sea and the Bristol Channel. The chart thus supplies the data by
means of which we can calculate the approximate time of high tide for
any one port from that of another.
[Illustration: FIG. 12.--CHART SHOWING THE RELATIVE TIMES OF HIGH TIDE
ON DIFFERENT PARTS OF THE BRITISH COAST
_George Philip & Son. Ltd._ _The London Geographical Institute._]
Although the time of high water varies so greatly on the same day over
such a small area of country, yet that time for any one place is always
approximately the same during the same relative positions of the sun,
earth, and moon; that is, for the same ‘age’ of the moon; so that it is
possible to determine the time of high water at any port from the moon’s
age.
The time of high tide is generally given for the current year in the
local calendars of our principal seaports, and many guide-books supply a
table from which the time may be calculated from the age of the moon.
At every port the observed high water follows the meridional passage of
the moon by a fixed interval of time, which, as we have seen, varies
considerably in places within a small area of the globe. This interval
is known as _the establishment of the port_, and provides a means by
which the time of high water may be calculated.
Before closing this short chapter on the general characteristics of the
sea shore we ought to make a few observations on the nature of the water
of the sea. Almost everyone is acquainted with the saltness while many
bathers have noticed the superior buoyancy of salt water as compared
with the fresh water of our rivers and lakes. The dissolved salts
contained in sea water give it a greater density than that of pure
water; and, since all floating bodies displace their own weight of the
liquid in which they float, it is clear that they will not sink so far
in the denser water of the sea as they would in fresh water.
If we evaporate a known weight of sea water to dryness and weigh the
solid residue of sea salt that remains, we find that this residue forms
about three and a half per cent. of the original weight. Then, supposing
that the evaporation has been conducted very slowly, the residue is
crystalline in structure, and a careful examination with the aid of a
lens will reveal crystals of various shapes, but by far the larger
number of them cubical in form. These cubical crystals consist of common
salt (sodium chloride), which constitutes about three-fourths of the
entire residue, while the remainder of the three and a half per cent.
consists principally of various salts of magnesium, calcium, and sodium.
Sea salt may be obtained ready prepared in any quantity, as it is
manufactured for the convenience of those who desire a sea bath at home;
and it will be seen from what has been said that the artificial
sea-water may be prepared, to correspond almost exactly with that of the
sea, by the addition of three and a half pounds of sea salt to about
ninety-six and a half pounds of water.
This is often a matter of no little importance to the sea-side
naturalist, who may require to keep marine animals alive for some time
at considerable distance from the sea shore, while their growth and
habits are observed. Hence we shall refer to this subject again when
dealing with the management of the salt-water aquarium.
The attractions of the sea coast are undoubtedly greater by day than at
night, especially in the summer season, when the excessive heat of the
land is tempered by the cool sea breezes, and when life, both on the
cliffs and among the rocks, is at its maximum. But the sea is grand at
night, when its gentle ripples flicker in the silvery light of the full
moon. No phenomenon of the sea, however, is more interesting than the
beautiful phosphorescence to be observed on a dark summer’s night. At
times the breaking ripples flash with a soft bluish light, and the water
in the wake of a boat is illuminated by what appears to be liquid fire.
The advancing ripples, as they embrace a standing rock, surround it with
a ring of flame; while streaks and flashes alternately appear and
disappear in the open water where there is apparently no disturbance of
any kind.
These effects are all produced by the agency of certain marine animals,
some of which display a phosphorescent light over the whole surface of
their bodies, while in others the light-giving power is restricted to
certain organs or to certain well-defined areas of the body; and in some
cases it even appears as if the creatures concerned have the power of
ejecting from their bodies a phosphorescent fluid.
It was once supposed that the phosphorescence of the sea was produced by
only a few of the lower forms of life, but it is well known now that
quite a large number of animals, belonging to widely different classes,
play a part in this phenomenon. Many of these are minute creatures,
hardly to be seen without the aid of some magnifying power, while others
are of considerable size.
Among the peculiar features of the phosphorescence of the sea are the
suddenness with which it sometimes appears and disappears, and its very
irregular variations both at different seasons and at different hours of
the same night. On certain nights the sea is apparently full of living
fire when, almost suddenly the light vanishes and hardly a trace of
phosphorescence remains; while, on other occasions, the phenomenon is
observed only on certain patches of water, the areas of which are so
well defined that one passes suddenly from or into a luminous sea.
The actual nature of the light and the manner in which it is produced
are but ill understood, but the variations and fitfulness of its
appearances can be to a certain extent conjectured from our knowledge
of some of the animals that produce it.
In our own seas the luminosity is undoubtedly caused principally by the
presence of myriads of minute floating or free-swimming organisms that
inhabit the surface waters. Of these each one has its own season, in
which it appears in vast numbers. Some appear to live entirely at or
near the surface, but others apparently remain near the surface only
during the night, or only while certain conditions favourable to their
mode of life prevail. And further, it is possible that these minute
creatures, produced as they generally are in vast numbers at about the
same time, and being more or less local, are greatly influenced by
changes of temperature, changes in the nature of the wind, and the
periodic changes in the tides; and it is probable that we are to look to
these circumstances for the explanations of the sudden changes so
frequently observed.
In warmer seas the phenomenon of phosphorescence is much more striking
than in our own, the brilliancy of the light being much stronger, and
also produced by a greater variety of living beings, some of which are
of great size, and embrace species belonging to the vertebrates and the
higher invertebrate animals.
Those interested in the investigation of this subject should make it a
rule to collect the forms of life that inhabit the water at a time when
the sea is unusually luminous. A sample of the water may be taken away
for the purpose of examination, and this should be viewed in a good
light, both with and without a magnifying lens. It is probable, too,
that a very productive haul may be obtained by drawing a fine muslin net
very slowly through the water. After some time the net should be emptied
and gently washed in a small quantity of sea water to remove the smaller
forms of life contained, and the water then examined at leisure.
Of course it must not be assumed that all the species so obtained are
concerned in any way with the phosphorescence of the sea, but any one
form turning up in abundance when collected under the conditions named
will probably have some connection with the phenomenon.
One may well ask ‘What is the use of this light-emitting power to the
animals who possess it?’ but this question is not easily answered. The
light produced by the glow-worm and other luminous insects is evidently
a signal by means of which they call their mates, and this may be the
case with many of the marine luminous animals, but it is evidently not
so with those which live in such immense numbers that they are simply
crowded together; nor can it be so with the many luminous creatures
that are hermaphrodite. It is a fact, however, that numbers of deep-sea
species possess the power of emitting light to a striking extent; and
the use of this power is in such cases obvious, for since the rays of
the sun do not penetrate to great depths in the ocean, these luminous
species are enabled to illuminate their own surroundings while in search
of food, and, in many cases at least, to quench their lights suddenly at
such times as they themselves are in danger.
CHAPTER II
_THE SEA-SIDE NATURALIST_
OUTDOOR WORK
Assuming that the reader is one who desires to become intimately
acquainted with the wonderful and varied forms of life to be met with on
the sea shore, or, hoping that he may be lured into the interesting and
profitable pastimes of the sea-side naturalist, we shall now devote a
chapter to the consideration of the appliances required for the
collection and examination of marine life, and to general instructions
as to the methods by which we may best search out the principal and most
interesting objects of the shore.
First, then, we shall describe the equipment of an enthusiastic and
all-round admirer of Nature--he who is interested in plant forms
from the flowering species down to the ‘meanest weed that grows,’ and is
always ready to learn something of any member of the animal world that
may happen to come within his reach. And this, not because we hope, or
even desire, that every reader may develop into an all-round naturalist,
but so that each may be able to select from the various appliances named
just those which would be useful for the collection and observation of
the objects which are to form his pet study.
The most generally useful of all these appliances is undoubtedly some
kind of case of the ‘hold-all’ type, a case into which specimens in
general may be placed for transmission from the hunting-ground in order
that they may be studied at leisure, and we know of nothing more
satisfactory than the botanist’s ‘vasculum.’ This is an oblong box of
japanned tin, fitted with a hinged front, and having both handle and
strap, so that it can be either carried in the hand or slung over the
shoulder. Of course almost any kind of non-collapsible box or basket
will answer the purpose, but we know of no utensils so convenient as the
one we have named. It is perfectly satisfactory for the temporary
storage of the wild flowers gathered on the cliffs, as it will keep them
moist and fresh for some considerable time; and for the reception of sea
weeds of all kinds it is all that could be desired, for it will
preserve them in splendid condition, and is so constructed that there is
no possibility of the inconvenience arising from the dripping of salt
water on the lower garments. Then, as regards marine animal-life in
general--starfishes, urchins, anemones, molluscs, crustaceans, fishes,
&c.--these may be conveyed away in it with a liberal packing of moist
weeds not only without injury, but in such a satisfactory condition that
nearly all may be turned out alive at the end of a day's work; and this
must be looked upon as a very important matter to him who aims at
becoming a naturalist rather than a mere collector, for while the latter
is content with a museum of empty shells and dried specimens, the former
will endeavour to keep many of the creatures alive for a time in some
kind of artificial rock pool in order that he may have the opportunity
of studying their development and their habits at times when he has not
the chance of visiting the sea shore for the purpose.
[Illustration: FIG. 13.--THE VASCULUM]
But although the vasculum is so generally useful for the temporary
storage and the transmission of the objects collected, yet it is not in
itself sufficient for all purposes. There are many marine animals so
small--but none the less interesting because they are small--that they
would probably be lost in a case containing a mass of sea weeds with
various larger creatures. These should be placed in small well-corked
bottles, and temporarily preserved in a little sea-water, or,
preferably, a tuft of one of the delicate weeds so common in our rock
pools. Others, again, though they may be larger, are of so fragile a
nature that they should be isolated from the general stock on that
account alone. Instead of bottles or tubes, small tin boxes may be used,
and these have the advantage of being unbreakable, though, of course,
they will not hold water. This, however, is of no consequence, as most
marine animals may be kept alive for some time in moist sea-weed quite
as well as in water.
When small animals are required for structural examination only, they
may be put into methylated spirit as they are taken, and when stored in
this way a much larger number may be put into the same receptacle; hence
the collector will often find it convenient to have a small supply of
this liquid while at his work.
A strong pocket-knife is essential for sea-side work. It serves to
remove those molluscs that adhere firmly to the rocks by suction, and
also others that fix themselves by means of a byssus of silken fibres,
as is the case with mussels. It will also be employed in the removal of
acorn barnacles, anemones, and small tufts of algæ, and may be useful in
cutting through the stouter weeds. Small sponges and other low forms of
life often form incrustations on the solid rock, and may be peeled off
with the aid of a knife. In the case of the last-named, however, as well
as with the anemones and other fixed animals, it is often far more
satisfactory to remove a small portion of the rock itself with the
animal attached, and for this purpose a small hammer will be of great
service.
A strong net of some kind is necessary in searching the rock pools, and
as suitable nets are, we believe, not to be obtained of the dealers in
naturalists’ appliances, it devolves on one to manufacture a net
according to his requirements.
The simplest form of net may be made by bending a piece of stout
galvanised iron wire into the form here shown (fig. 14), and firmly
wedging the two straight ends in a short piece of strong metal tube
which will also serve as a ferrule for the attachment of a tough handle.
Such a circular frame although satisfactory for a net to be used in
fresh-water ponds and streams, is not nearly so suitable for the
irregular rocky pools to be met with on the sea coast, for it will not
enable one to search the numerous corners and crevices into which many
marine creatures will retire on being disturbed, but it may be greatly
improved by bending the side opposite the ferrule into a moderately
sharp angle and then turning the angle slightly upward, as shown in fig.
15.
[Illustration: FIG. 14.--WIRE RING FOR NET]
[Illustration: FIG. 15.--NET FRAME WITH CURVED POINT]
Another very convenient net frame may be made by bending the wire into a
rhomboidal form (fig. 16), the ferrule being attached by means of two
short, straight ends at one of the angles. The opposite angle will serve
the purpose of searching into the crannies of the rocks, while the
straight sides will prove very useful in removing the objects that lie
on the sandy bottoms so commonly seen in rock pools. The semicircular
net shown in fig. 18 will also prove useful for working on sands or for
scraping the flatter surfaces of weed-covered rocks.
[Illustration: FIG. 16.--RHOMBOIDAL FRAME FOR NET]
The material of the net should be some kind of strong gauze, or a
loosely-woven canvas. Leno answers very well, but is somewhat easily
torn, and will have to be frequently renewed. This, however, may be
avoided to a great extent if, instead of sewing the gauze directly round
the wire, a strip of strong calico be first attached to the frame, and
the gauze then sewn to the calico; for it will be understood that any
fragile material placed round the wire will soon be worn through by
friction against the rugged surfaces of the rocks and stones. The net
itself should not be very deep, and should have no corners; and as to
the length of the handle, that will be determined by the fancy of the
collector, or by the character of the ponds to be searched, but a tough
walking-stick with a crook handle will generally answer all purposes,
the crook being itself frequently useful for removing the larger weeds
and other obstructions.
[Illustration: FIG. 17.--RHOMBOIDAL NET]
[Illustration: FIG. 18.--SEMICIRCULAR NET]
[Illustration: FIG. 19.--THE DREDGE]
Although the net, as above described, will answer the requirements of
nearly all young collectors, yet there may be some, who, not satisfied
with the exploration of the rocks and pools exposed when the tide is
out, desire to know something of the creatures that live entirely beyond
low-water mark, where the water is generally too deep for work with a
hand net. To such we recommend a small dredge that may be lowered from a
boat and then drawn along the bottom. A good form of dredge is shown in
fig. 19, and a little skill and ingenuity will enable anyone to
construct one with the help of our illustration; but, seeing that the
best work is to be done on rough bottoms, it is absolutely necessary
that both frame and net should be made of the stoutest materials that
can be conveniently employed.
[Illustration: FIG. 20.--THE CRAB-POT]
Those who have ever accompanied a fisherman while taking a pull round to
examine the contents of his crab or lobster pots will probably have
noticed what strange creatures, in addition to the edible crabs and
lobsters, sometimes find their way into the trap. These creatures are
often of great interest to a young naturalist, and it will repay him to
take an occasional trip with a fisherman in order to obtain them; or,
still better, to have a crab-pot of his own. The writer has obtained
many good specimens by means of an inexpensive trap, on the same
principle as the ordinary crab-pot, made from an old metal bird-cage of
rather small size. The bottom was removed, and a very shallow bag of
thick canvas fixed in its place; and some of the wires were cut, and
bent inwards so as to allow the easy entrance of moderately large
crustaceans and other creatures, while at the same time they served as a
barrier to their escape. Such a trap, baited with pieces of fish, and
let down to a rocky bottom, will enable the young naturalist to secure
specimens that are seldom seen between the tide-marks; and the animals
thus obtained will include not only those larger ones for which the
opening was made, but also a variety of smaller creatures that may enter
between the wires of the cage. Some of the latter may, of course, escape
by the same way as the trap is being hauled up for examination, but this
is not so likely to occur if the canvas bottom is of a material so
loosely woven that water can pass through it very freely. It will, of
course, occur to the reader that the insertion of a stone or other
weight will assist in sinking the trap; also that the ordinary door of
the cage forms a ready means by which the captives may be removed.
[Illustration: FIG. 21.--AN OLD BIRD-CAGE USED AS A CRAB-POT]
One thing more: make it a rule never to go out collecting natural
objects of any kind without a note-book and pencil. This, to the
beginner who is anxious to get to his work, with the idea only too
prevalent with the amateur that the success of his labours is to be
measured only by the number of specimens obtained, may seem quite an
unnecessary part of the equipment. But it must be remembered that there
is much to _observe_ as well as much to collect on a well-selected
coast; and that without the aid of the book and pencil a great many of
the observations made will be forgotten, and thus much interest that
would otherwise be attached to the objects permanently preserved will be
lacking.
The above appliances include the only necessary equipment of the
sea-side naturalist, with the exception of a few required for occasional
use in connection with the species of a somewhat restricted habitat, and
the outfit of the sea angler. The former will be dealt with in the
chapters where the species concerned are described, while the subject of
sea angling is of such general interest that we propose to devote a
short chapter exclusively to it.
It may seem hardly necessary to discourse on the nature of the attire
most suitable for sea-side work, since the majority will readily form
their own opinions on this matter, but perhaps a few words of advice to
the inexperienced may not be altogether out of place. First, then, make
it a rule to wear no clothing of any value. The work will lead the
enthusiast over slippery weeds, on treacherous boulders, over rocks
covered with sharp acorn shells, and among slimy and muddy stones, and
many a slip may occur in the course of a day’s work. Large pockets
specially but simply made by sewing square pieces of lining on the
inside of an old jacket are a great convenience; a cap rather than a
brimmed hat should be worn unless the latter be considered essential for
protection from a burning summer’s sun; and a pair of old shoes,
preferably with rubber soles, are just the thing for both rough and
slippery rocks, as well as for wading through shallow waters. Other
details we can safely leave to the fancy of the reader himself.
Now comes the most important question ‘Where shall we go?’ Fortunately
we are favoured with a great extent of coast-line considering the area
of our country, but the character of the coast is so diversified, both
with regard to its scenery and its life, that the naturalist will do
well to carefully select his locality according to the objects he
desires to study. The east coast of England is not generally noted
either for variety or abundance of marine life, and the same is true
both of the south-east and a large portion of the south coast. In some
places the beach is formed of an unbroken stretch of sand on which one
may walk for miles without seeing any sign of life, with the exception
of an occasional empty shell and a few fragments of dried sea-weed
washed in by the breakers during a recent storm; while at the same time
the cliffs, if such exist at all, are not very generous in their
production of the fauna and flora that are characteristic of the shore.
But even on the coasts referred to there are, here and there, isolated
spots where the uplands jut into the sea, giving rise to bold
promontories, at the foot of which are the fallen masses of rock that
afford protection to a moderate variety of truly marine life, while the
rough bottoms beyond yield numerous interesting forms that may be
secured by means of the dredge or suitable traps. Such spots are to be
found where the chalk hills abut on the sea, as at Flamborough and
Beachy Head, but it is in the neighbourhood of Weymouth that the English
coast really begins to be of great interest to the naturalist. From here
to the Land’s End almost every part of the shore will yield a great
variety of life in abundance, and the same is true of the rocky coasts
of the west, and also of the more rugged shores of the Isle of Wight.
As an ideal hunting-ground one cannot do better than to select one of
the small fishing towns or villages on the rocky coasts of Devon and
Cornwall. With such a spot as his headquarters the most enthusiastic
sea-side naturalist will find ample employment. The exposed rocks and
rock pools yield abundance of life; and if these be searched when the
tide is out, there will remain plenty of sea angling and other
employments to occupy him at other times.
We will now describe the actual work of the sea-side naturalist, giving
the necessary instructions for the observation and collection of the
various living things he will meet with.
First, then, with regard to work on the cliffs, a very few words will
suffice; for, seeing that the objects of interest to be met with here
will consist principally of the various flowers that are peculiar to or
characteristic of the sea shore, and certain insects and other creatures
more or less partial to a life on the cliffs, we may regard these as
coming within the range of the general work of the botanist,
entomologist, &c.; and since instructions for the collection and
preservation of such objects have already been given in former works of
this series, we may pass them over at once in order to deal with those
objects which are essentially marine.
It has already been hinted that the right time for collecting on the
shore is when the tide is at its lowest; and in order that the best work
may be done the collector should consult the local tide-tables, or
calculate, if necessary, the time of high tide from the establishment of
the port; and, of course, the period of spring tides should be selected
if possible. The time during which work should continue must be
regulated according to the enthusiasm of the collector or the time at
his disposal, but, as a rule, it is advisable to be on the scene of
action about three hours before the time of low tide, with a
determination to work continuously until the lowest ebb of the water.
On reaching the beach it is always advisable to start by examining the
line of miscellaneous material at high-water mark, along which may be
found quite a variety of objects, more or less interesting, which have
been washed in by the breakers, especially just after a storm, together
with numerous scavengers of the shore that perform a most useful work in
devouring the decomposing organic matter that would otherwise tend to
pollute the air.
Here we may find many useful and interesting objects of both the animal
and vegetable worlds. Among the former are the empty shells of both
univalve and bivalve molluscs, some of which are more or less worn by
the action of the waves, while others are in splendid condition for
examination and study. Here, too, are various species of sea firs and
the skeletons of sponges; the shell of the cuttle-fish, and occasionally
a cluster of the eggs of this creature--the sea-grapes of the fishermen;
also the egg-cases of the skate and the dog-fish--usually empty, but
sometimes enclosing the young animal still alive; and, lastly, we
frequently meet with portions of the skeletons of fishes in a perfect
state of preservation, the animal matter having been cleared away by the
combined action of the scavengers previously referred to. Then, as
regards the vegetable world, we often find beautiful specimens of
sea-weeds along the high-water mark, some of which are rarely met with
in the rock pools, since they are species that have been detached from
beyond the line of low water, and washed up by the breakers.
On turning over the debris thus thrown on the beach we intrude on the
privacy of numerous living creatures which immediately scamper away to
find a new hiding-place. These consist principally of sand-hoppers, but
occasionally we find members of the insect world engaged in the same
useful work in addition to the numerous flies that perform their office
of scavengers in the bright sunshine on the top of the matter that
supplies them with food.
It will be interesting to capture a few of these scavengers, and to
compare them with others of the same order obtained from different
localities. Thus, the flies may be compared with the more familiar house
fly, and the sand-hoppers of high-water mark with similar crustaceans to
be afterwards obtained lower on the beach.
Attention should now be given to the rocks left exposed by the
retreating tide, and it is here that the real work begins. Examine each
rock pool as soon as possible after it is no longer disturbed by the
waves. Remove any tufts of corallines or other weeds required for study
or preservation, and simply place them, pro tem., in the vasculum or
other receptacle provided for the purpose. These will form a useful
protective packing for other objects that are to be carried away, so
that it will be advisable to secure a moderate amount rather early, even
though they may not be required for any other purpose. Live molluscs,
crabs, small fishes, &c., may all be put in the receptacle with this
weed, and all will probably be still alive after the collecting and the
homeward journey have been completed. Probe the corners of the pool
with the point of the net, and also sweep the net upward among the weeds
to remove any creatures that seek shelter among the fronds. Tufts of
corallines and other weeds should be searched for the small and delicate
starfishes that live among them, and any stones that may cover the
bottom of the pool should be lifted. Anemones may be removed from the
rocks by means of a rather blunt knife; but, if possible, it will be
better to chip off a small piece of the rock with the anemone attached
to it, and wrap it lightly round with a tuft of soft weed previous to
placing it in the collecting case.
A number of rock pools should be searched in this manner, but those
chosen should vary as much as possible in general character. All very
small and delicate objects should be isolated from the general stock,
and placed, with the usual packing material, either in tin boxes or
small wide-mouthed bottles; and if any animals taken are not required
alive, but only for preservation, they should be preferably killed at
once and then stored in a separate case. Some creatures are easily
killed by simply dropping them into a bottle of fresh water, but others
should be covered with methylated spirit. It should be mentioned,
however, that the natural appearance of some of the crustaceans is quite
destroyed by strong spirit, which soon makes them look as if they had
been boiled. Some species are changed in this way much more readily than
others; and, until sufficient experience has been gained to enable the
young collector to distinguish between them, it will be advisable to
kill and temporarily preserve crustaceans in spirit that has been
considerably diluted with water--about two parts of water to one of
spirit, for example. Further, there are certain fragile starfishes that
have a way of breaking themselves into pieces when dropped into spirit,
or even when suddenly disturbed in almost any other manner. These must
always be handled gently, and if it is required to kill them for
preservation, the best way will be to put them in a little salt water,
and then gradually add fresh water until the desired result is obtained.
Perhaps the most productive of all sea-shore work is the turning over of
the stones of various sizes near the low-tide mark, and the examination
of the chinks and sheltered hollows of the rocks that are left uncovered
for but a short period. This work should be carried on as near the
water’s edge as possible, closely following the receding tide; and the
collector must now be prepared with a number of small bottles or tins
for the isolation of small and delicate specimens. He must also be on
the alert for numerous examples of protective resemblance, in which the
animals concerned so closely resemble their surroundings in colour and
general character of surface that they are detected only by careful
observation, while the difficulty of identification is still further
increased in instances where the creatures remain perfectly still even
when disturbed.
[Illustration: FIG. 22.--A YOUNG NATURALIST AT WORK]
Under the stones all manner of animals--fishes, crustaceans, worms,
molluscs, starfishes, anemones, &c.--will be hiding until covered by the
next tide. Some of these will be found on the ground beneath the stones,
and others attached to the under surfaces of the stones themselves;
therefore both should be carefully examined, attention being given at
first to the more active species that hurry away with all speed towards
a new shelter as soon as they find themselves exposed to the light; the
less active creatures may then be secured at leisure.
The tide will not allow the collector a great deal of time in which to
turn over the most productive stones--those close to the low-water mark,
so there is but little opportunity of observing the movements and other
interesting habits of many of the animals found; hence it is advisable
to secure a good variety of living specimens, especially of the less
familiar species, in order that they may be placed in some kind of
aquarium, temporary or otherwise, for observation at home.
[Illustration: FIG. 23.--A GOOD HUNTING-GROUND ON THE CORNISH COAST]
One thing more remains to be done while the tide is well out, and that
is to examine the weed-covered rocks near the water’s edge. Lift the
dangling weeds and carefully search the rocks for those low forms of
animal life that form incrustations on the surface, as well as for new
species of anemones, sea firs, &c. Lastly, look well into the dark and
narrow chinks of the rocks, for here several species of lowly animals
that are hardly met with elsewhere may be found, and also certain
crustaceans that delight to squeeze their bodies into the remotest
corner of a sheltered niche.
CHAPTER III
_SEA ANGLING_
We do not propose dealing with this subject from the point of view of
the angler, but rather that of the naturalist. The former is actuated
principally, if not entirely, by the mere love of sport; or, it may be,
to a great extent by the desire to obtain a supply of fish for food; and
he generally estimates the success of his expeditions not by the number
of _species_ captured, but by the total weight of his catch, no regard
being paid, as a rule, to the inedible specimens. The naturalist,
however, does not desire weight, or sweetness of flesh. He works the
greatest possible variety of habitats, with the object of determining
the number of species inhabiting the locality and of learning as much as
possible of their general form, habits, and adaptations of structure to
habits. His success is measured by the number and variety of species
caught, and he pays but little attention to superiority of size or
weight, or to the estimated market value of his haul. The element of
sport may enter more or less largely into the pleasure of his
occupation, but the main end in view is to learn as much as possible of
all the species obtainable.
Further, our remarks will not include the subject of the different kinds
of fishing usually resorted to by sea anglers, but will be confined
almost exclusively to the simple means of catching the common species
that frequent the immediate neighbourhood of the shore.
If the reader will follow the general instructions given in Chapter II.
on the outdoor work of the marine naturalist, he will undoubtedly make
the acquaintance of a considerable variety of interesting species which
may be captured in the rock pools, found under stones at low tide, or
obtained by means of a small dredge; but his knowledge of our littoral
fishes may be appreciably extended by the occasional employment of rod
and line from rocks and piers, or from a small boat in close proximity
to the shore.
The appliances required are of a very simple nature, and not at all
costly. The long, heavy rod and strong tackle of the sea angler and
professional fisherman are not at all essential to our purpose, for our
work will be confined almost exclusively to shallow water, and the fish
to be caught will be chiefly of small size. True it is that one may
occasionally find his light tackle snapped and carried away by the
unexpected run of a large fish, for cod and other large species often
approach close to the shore, and bite at baits intended for the smaller
fish that make their home among the partly submerged rocks of the coast;
but such surprises will not frequently occur, and the young naturalist
may learn all he wants to know of the fishes of our shallow waters with
the aid of a light rod of about nine or ten feet and one or two light
lines of no great length.
It must not be understood, however, that we assume the reader’s
disinclination to know anything of the inhabitants of deep water, but
rather that we consider the whole subject of deep-sea fishing quite
beyond the scope of this work. It is a fact that quite a large number of
species, the forms and habits of which are extremely interesting, live
exclusively on deep bottoms. These should undoubtedly be studied by all
who are interested in the various phases of marine life; but unless the
reader is prepared to practise sea fishing in all its branches--to put
his trust in the restless sea, supplied with all the necessary heavy
gear, and to risk those internal qualms that arise from the incessant
swaying of the boat on open waters, he should make arrangements with the
professional deep-sea fisher--preferably a trawler--for the supply of
those disreputable species that invariably form part of the haul, while
the better-known food fishes can always be obtained from dealers for
purposes of study.
On one occasion we had a rather unique and very successful interview
with a friendly trawler. She was sailing slowly towards her station in a
south-western fishing port, while two of her crew were clearing her
nets, and throwing all refuse into the sea. We rowed behind her in order
to see the nature of the rejected portion of the haul, and finding that
it included specimens of interesting fishes of ill repute, dead but
perfectly fresh, we followed her track, and collected a few for future
examination. Presently our movements were watched from aboard, and we
were invited to pull up to larboard, where a short explanation as to our
wants led to the acquisition of quite a variety of deep-sea life,
including several species of fishes not often seen on land, crabs,
shelled and shell-less molluscs, worms, star-fishes, and various lowly
organised beings, many alive and in good condition, together with
several good food fishes thrown in by way of sympathy. There is no doubt
that a naturalist can obtain much more deep-sea life with the aid of a
friendly trawler than by any amount of ‘fishing’ with ordinary tackle
from a boat; and this without the necessity of going to sea at all, if
he will only take the opportunity of examining the nets as the boats are
stranded on their return.
But now to return to our angling:--We have to provide a light rod, about
ten feet long, with a winch, and a line of twisted silk or other thin
but strong material; also a light hand line, and a supply of gut, leads,
shot, and hooks, together with one or two small floats, and a few bait
boxes.
We do not, as a rule, recommend the amateur angler to use both rod and
hand line at the same time, for the attempt to do this leads to the
neglect of both. In the end it is not likely to lead to any gain, so
many fish being lost through the inability to strike at the moment a
bite is given, and so much time having to be devoted to the baiting of
hooks rather than to the direct management of the lines. In most cases
the rod is much more convenient than the hand line. The young collector
will meet with the greatest variety of species in rocky and weedy
places, where abundant shelter exists for those fishes that prefer to
keep well under cover, and any attempt with a hand line in such spots
will certainly lead to frequent loss of hooks, and often of lead, line,
and temper. Such a line must be reserved for fishing on sandy bottoms,
while the ten-foot rod recommended will enable the angler to do good
work in the rockiest parts without much danger of fouling; and, in fact,
to fish anywhere along the coast.
The arrangement of hooks and lead must necessarily depend on the
character of the place to be worked, but in all cases we strongly
recommend no such multiplicity of hooks as is made use of by fishermen
and others who fish for food. In their case the use of so many hooks
often pays them well; but, as we have previously hinted, the naturalist
does not desire quantity of fish so much as variety of species. Further,
there is no necessity to make his work heavy and arduous. His desire is
not to spend an undue proportion of his time in baiting hooks, but to
have his line so under control that he is ready to strike at any moment,
and to be able to alter the conditions of his work as often as his ideas
or the conditions change.
In rugged and weedy places the hooks must be kept free from rocks and
weeds. This may be done by letting down the rod line with a lead at the
bottom, and one or two hooks fastened to gut at such a level as to keep
quite clear of weeds. A much better arrangement, and one which we
ourselves almost invariably employ, consists of a light lead, as a rule
not exceeding an ounce in weight, fastened at the end of the line, and
below it a few feet of gut terminating in a single hook. With such
tackle it is of course necessary to determine previously the depth of
the water, in order to adjust the line to such a length that the hook
keeps clear of rocks and weeds, and a float may be used if desired.
[Illustration: FIG. 24.--ROUND BEND HOOK WITH FLATTENED END]
We do not recommend a float for the general work of the marine
collector, for it is a decided advantage to be prepared to bring the
bait to any level from bottom to surface, especially when the water is
so clear that the fish may be seen swimming, in which case one is often
impressed with the desire to capture a specimen in order to establish
its identity, and for such work as this a float is superfluous. If,
however, a float is used, it should be a sliding one, so that it may be
adapted to the rising and falling of the tide.
[Illustration: FIG. 25.--LIMERICK HOOK, EYED]
Of hooks there is a great variety to choose from, differing in the form
both of the curve and of the end of the shank. As to the curve, those
with a decided twist are best adapted to our purpose, chiefly on account
of the fact that sea fishes generally have larger mouths than
fresh-water species of the same size, and are consequently better held
with a twisted hook. The shanks of sea hooks are either flattened or
eyed, and each is as good as the other providing the snood is firmly
attached; but some amateurs find a greater difficulty in attaching the
snood to the former than to the latter.
Gut snoods are recommended for our purpose, and fig. 26 shows one method
by which they may be fastened to a flattened shank, while fig. 27
illustrates the figure-of-eight knot by means of which the eyed shank
may be firmly secured. The gut should be soaked for some hours in cold
water previous to tying, and it may be kept soft for some considerable
time by giving it a few hours’ immersion in a solution of
glycerine--about one part of glycerine to four or five parts of
water.
[Illustration: FIG. 26.--METHOD OF ATTACHING SNOOD TO FLATTENED HOOK]
Small hooks will be most suitable for our purpose; and if the reader
finds any difficulty in attaching the snood firmly, he may purchase
suitable hooks ready mounted on gut, though, of course, these are more
expensive than the flattened or eyed hooks generally used for
sea-fishing. Such small and fragile hooks may be occasionally snapped
off by the run of a vigorous fish of moderate size, therefore it is
advisable to have a supply of larger hooks, ready fixed on strong
snoods, to be used when it is found that the shore is frequented by
larger fishes than those generally caught close to land.
[Illustration: FIG. 27.--METHOD OF ATTACHING SNOOD TO EYED HOOK]
When fishing with a rod and line from rocks, or from piers, the
foundations of which are covered with large weeds, the bait will
frequently be carried by currents among the weeds and snapped off when
endeavours are made to release the hook. This will especially be the
case when the hook is a few feet below the lead, as we have already
suggested it should be. To reduce the frequency of such mishaps, it will
be a good plan to weight the gut below the lead by means of a few split
shot. In fact, in sheltered places, where the water is not disturbed,
these shot may take the place of the lead, but little weight being
necessary for rod fishing in such localities.
The amateur sea angler is often in great doubt as to the best bait to
use; and, believing that a certain kind of bait is absolutely necessary
for his work in some particular spot, is often at a loss to obtain it.
This bait difficulty is evidently a prevailing one among amateur sea
fishers, if one may judge from the frequent questions asked as to the
best or proper bait to use, and from the very common ‘Can you oblige me
with a little bait?’
This latter question, we believe, is frequently the outcome of
carelessness or laziness on the part of the asker. He has not the
forethought, born of enthusiasm, that would lead him to procure a
suitable bait, at a convenient time, previous to starting off on his
angling expedition, but rather depends on the possibility of being able
to beg or otherwise secure sufficient for his purpose at the time; yet
there are so many good baits that are easily secured at the proper time
and place that the enthusiastic angler need never be at a loss. Some of
these may be collected by himself at low tide, others may be obtained
from local fishermen, or from the tradesmen of the town or village.
[Illustration: FIG. 28.--THE LUGWORM]
Some anglers seldom collect their own bait, either purchasing it or
employing some one to collect it for them; but we are of opinion that
the pleasure of a day’s fishing begins here, and especially so when the
angler is of the naturalist type, for he will frequently learn more of
the nature and habits of living creatures during one hour’s
bait-collecting than during three or four hours’ angling. It is true
that the work in question is often a bit laborious, particularly on a
warm day, and that it may be frequently described as dirty and odorous;
but what is that to one who is interested in his employment, and who
derives pleasure in doing his own work?
Fishermen often use lugworms for bait, and although these constitute one
of the best baits for their own fishing, they are not so suitable for
the purposes of the amateur angler, fishing with small hooks close to
shore. They may be dug out of the sand when the tide is out, and are
most abundant where the sand is mixed with mud. A spade should be used,
and this should be thrust deep into the sand, selecting those spots
where the holes or burrows of the worms most abound. Lugworms should be
used whole; and being of large size, are suitable for baiting large
hooks only. They may be kept alive in wet sand or sea-weed, preferably
the latter for convenience, and stored till required in a wooden box.
Ragworms also afford good bait, and are particularly adapted for shore
angling with small hooks. Almost all the fishes that frequent our shores
take them readily, but they are not to be found in all localities. They
are to be taken, though not usually in large numbers, on rocky shores
where numerous stones lie among the somewhat muddy deposits of the more
sheltered nooks, where they may be seen on turning over the stones. The
best situation for ragworms, however, is the more or less odoriferous
mud so frequently deposited in the estuaries of rivers and in landlocked
harbours. Here they maybe dug out in enormous numbers with a spade,
attention being directed to those spots where their burrows are most
numerous. They are best stored with a little of the mud in a shallow
wooden box provided with a sliding, perforated lid.
[Illustration: FIG. 29.--THE RAGWORM]
Failing a supply of the marine worms just mentioned, the common
earthworm may be used as a substitute, but it is decidedly less
attractive to the fishes; and the same may be said of gentles--the larvæ
or grubs of flies. The latter may be bred in large numbers by simply
placing a piece of liver in the soil with only a small portion exposed.
If this is done in the summer time, hundreds of eggs will soon be
deposited on it, and in about a week or so it will be found to be a
living mass of fat white grubs, perhaps more useful to the fresh-water
angler than to his marine counterpart.
Among the so-called shell fish of the class _mollusca_, mussels,
limpets, cockles, and whelks are all largely used for bait. The last of
these are too large for our purpose, but form a splendid bait for
deep-sea fishing, while the other three, and especially the mussels, are
well suited for shore work. Mussels, in fact, provide one of the best
possible baits for almost all kinds of shore fishing, the only drawback
being the excessive softness of their bodies, which enables them to be
easily torn from the hook. When small hooks are used, mussels of a small
size may be used whole, or the larger ones may be divided into portions
of suitable size; and in any case it will be found a good plan to tie
the bait to the hook with a short piece of cotton thread.
[Illustration: FIG. 30.--DIGGING FOR BAIT]
Mussels are not easily opened without injury, and consequently some
anglers give them a short immersion in hot water, to kill the animal and
thus cause the shell to gape. As far as our own experience goes, the
value of the bait is not deteriorated by this treatment, though some are
of opinion that it is not so attractive after scalding. Mussels are
opened, when alive, much in the same way as oysters, but the valves of
the shell fit together so closely that it seems at first almost
impossible to insert a knife between them. This, however, can be done
with ease if one valve is first made to slide a little way over the
other by pressing it with the thumb. This being accomplished, the two
valves should not be separated by the mere force of the knife, for this
would tear the animal within, and render it more or less unfit for its
purpose; but first direct the edge of the knife towards the _adductor
muscle_, by means of which the animal pulls its valves so firmly
together, and then cut through this close to the inner surface of the
upper valve. This valve can then be lifted without injury to the soft
parts, and the whole animal removed from the other valve by cutting
through the same muscle close to it.
[Illustration: FIG. 31.--METHOD OF OPENING A MUSSEL]
Between the two lobes of the _mantle_--the soft covering on both sides
of the animal that previously lined the shell--will be seen a brown,
fleshy, tongue-like body. This is the ‘foot’ of the mussel. The point of
the hook should first be run through this, and then from side to side
through the mantle, and finally through the adductor muscle previously
described. If this is carefully done, there will be little fear of the
bait becoming detached unless it is subjected to rough usage, and still
less if it is tied round the shank of the hook by means of a short piece
of cotton thread.
It is probably superfluous to mention to the reader the fact that
mussels are to be found on almost every rocky coast, where they may be
seen attached to the rocks by means of a bunch of silky fibres called
the _byssus_; and that, failing this, they are to be obtained from
almost every fisherman and fish-dealer; if, however, these molluscs are
not to be obtained, cockles may be used as a substitute, though it will
probably be found that they are appreciably inferior, except when
fishing for dabs and plaice on sandy shores, in which case they are
highly satisfactory. Cockles abound on most sandy coasts, where they
live a little below the surface; and are usually obtained by means of an
ordinary garden rake. Sometimes we meet with them in large numbers in
the estuaries of rivers, where they lie buried in the banks of mixed
sand and mud that are left exposed at low tide.
Limpets are extensively used for bait in some places, especially by
amateur anglers; and often with good results. They should always be
removed from the rocks without injury, and this is no easy matter to
those who do not know how to deal with them. If taken completely by
surprise, one sharp, but light tap on the side of the conical shell will
successfully detach them from their hold; or they may be raised by means
of the blade of a strong pocket-knife that has been thrust beneath the
cone.
For our work small limpets will prove far more satisfactory than large
ones, and these may be used whole; but if the limpets are too large for
the hooks employed, the soft, upper part of the body only need be used.
It is not an easy matter to remove fresh limpets from their shells
without destroying this soft portion of the animal, but if placed for a
minute or so in hot water they come out quite easily, and are apparently
none the less attractive as bait. Some fishermen on the Cornish coast
always collect the largest limpets for bait, remove them from their
shells by means of hot water, and arrange them on the rocks to become
partly dry. When required for bait, the soft parts only are used, but
these, having been more or less hardened by the drying process, hold
much better on the hook than when fresh.
And now, after mentioning the fact that land snails are occasionally
used, though, we believe, with no very considerable success, for sea
fishing, we will note a few baits derived from the higher head-footed
molluscs--the squid, cuttle-fish, &c. There are several species of these
peculiar molluscs, but the common squid and the common cuttle of our
seas, and especially the former, is highly prized as bait. It may be
obtained from fishermen, who frequently haul it in their nets; but if
supplied alive and fresh from the sea it must be handled very
cautiously, otherwise it may discharge the contents of its ink-bag over
one with the most unpleasant results. It is certainly best used while
fresh, though some suspend it until dry, and then store it for future
use, in which case it will require soaking in water when required. The
thin tentacles or arms are very convenient for baiting small hooks,
though other parts of the body, cut into narrow strips, will serve the
purpose of the angler equally well.
Of the crustaceans, shrimps and prawns, and various species of crabs are
used as bait. Shrimps and prawns are used whole for catching flat-fish,
but small pieces are better when fishing for smelt and other small
species of fish that swim close to shore. Little pieces of the flesh of
the crab are also well adapted for baiting hooks of small size, and will
prove very attractive to almost all kinds of fish. Small crabs, however,
may be used whole, but are of little use except when soft--that is, just
after the shedding of their shells, and before the new skin has had time
to harden. Such crabs may be found under stones and in other
hiding-places at low tide, for at such times they keep well secluded
from their numerous enemies by whom they are greedily devoured while in
this helpless and unprotected condition.
The hermit-crab, which selects the empty shell of a whelk or winkle for
its home, is probably well known to our readers. The protection afforded
by such a home is absolutely necessary to its existence, since its
abdomen has no other covering than a soft, membranous skin. This soft
abdomen is frequently used as a bait with great success, as well as the
flesh of the larger claws.
If the shell from which the hermit-crab is taken be broken, a worm,
something of the nature of the common ragworm, will almost always be
found, and this also is very serviceable as bait.
In addition to all the baits previously named there are several other
good ones, many of which are to be obtained almost everywhere. Among
these may be mentioned strips cut from the mackerel, herring, or
pilchard, preferably with a portion of the silvery skin attached; also
thin strips of tripe. Sand-eels, which may be dug out of the sand near
the water’s edge, are very useful, and may be cut into pieces for
baiting small hooks. Further, a large number of artificial baits are
employed in various kinds of sea fishing, but as these are not
essential for the work we have in hand we do not propose describing them
in detail.
Now let us suppose that we are about to try our luck at sea angling, on
some rocky coast, such as that of Devon and Cornwall, our object being
to determine, as far as possible, what species of fishes frequent the
immediate neighbourhood of the shore. And this is not all; for, when
fishing with rod and line on such a coast, it frequently happens that we
land some species of crab that has been attracted to our bait. The
ordinary angler would regard such crab as an intruder, and, we are sorry
to say, would often consider it his duty to crush the unfortunate
crustacean beneath his foot. But it is far different with the
naturalist. He favourably regards all creatures from which something may
be learnt, and is as anxious, as a rule, to gather information
concerning the habitats of one class as of another. In fact, we may go
still further, and combine crab fishing with ordinary angling, both in
one and the same expedition, by letting a small crab-pot down into deep
water among the rocks, and allowing it to remain while the angling is
proceeding.
We select a spot where there are several feet of water close to a
perpendicular rock, varied and broken by numerous holes and crevices, in
which various species of fishes and crustaceans habitually hide.
Such a situation is an ideal one for a young naturalist, for not only
does he obtain the greatest variety of species here, but the takings
will surely include some of those remarkably interesting rock-dwelling
fishes that differ from our ordinary food fishes in so many points of
structure, all of which, however, display some interesting adaptation to
the habits and habitats of the species concerned.
Our apparatus consists of nothing more than rod and line, one or two
small leads, a supply of hooks on gut snoods, a box of bait, and a
waterproof bag in which to pack the specimens we desire to preserve.
We first determine the depth of the water by means of a lead on the
_end_ of the line, and then tie the hook on the end with a small lead a
few feet above it, and fish in such a manner that the hook is just on
the bottom, or, if the bottom is covered with weeds, the hook should be
kept just clear of fouling them.
The peculiar rock fishes so common on such a coast as this on which we
are engaged need special treatment at the hands of the angler. They hide
in their holes, watching for the unwary creatures on which they feed,
and, pouncing upon them suddenly, rush back to their snug little nooks
in which they can secure themselves firmly by means of the sharp, hard
spines with which their bodies are furnished. When these fishes seize
the bait offered them--and they are not at all fastidious in the choice
of their viands--they should be hooked and pulled up with one vigorous
sweep of the rod, or they will dart into their homes, from which it is
almost impossible to dislodge them.
[Illustration: FIG. 32.--FISHING FROM THE ROCKS]
In addition to these, there will be various other species that require
gentler treatment, and may be hooked and landed much in the same manner
as fresh-water fishes, since they are free swimmers, usually keeping
well clear of the rocks and weeds.
If the day is calm, and the water clear, the sea angler will often be
able to watch various fishes as they swim, and to bring the bait gently
within their reach; and here we find the advantage of the rod as
compared with the hand line. Sometimes quite a shoal of small fishes may
be seen sporting near the surface, and, as a rule, there will be no
difficulty in obtaining one for identification and study. These are
generally best secured by means of small hooks, with but very little
bait, and will often bite freely at the tiniest fragment of worm on an
almost naked hook.
After the water has been searched at all depths, it will be well to
allow the bait to rest quite on the bottom, even at the risk of losing a
hook or two in the weeds and rocks. This may enable one to take some
fresh species of fish or to secure a crustacean or other creature that
is not often found between the tide-marks. Care should be always taken,
however, to keep the hook well clear of the weeds that grow on the sides
of the rock, and sway to and fro with every movement of the restless
waters.
Angling from piers may be pursued much in the same manner as described
above in those places where the bottom is rocky, but since the chances
of hooking large fish are greater here than close to shore, it is
necessary to be provided with stronger tackle and larger hooks. If,
however, the bottom is sandy, the rod tackle may be modified by placing
the lead at the bottom, and arranging two or three hooks above it, about
one or two feet apart, the lowest one being near the lead. With such an
arrangement the line may be cast some distance out, but for angling
close to the pier itself there is, perhaps, nothing better than the
single-hook arrangement suggested above, for with this one may fish on
the bottom and at all depths without any alteration in the tackle being
necessary.
If, however, the rod line is to be cast as suggested above, or if a hand
line is to be similarly used, the following hints may be useful as
regards the arrangement of hooks and lead.
The line itself may be of twisted silk or hemp, terminated with about a
yard of strong gut. The lead, preferably of a conical or pear-shaped
form, should be placed at the extreme end, and its weight regulated
according to the necessities of the occasion. A few ounces of lead are
quite sufficient where there are no strong currents, but it is well to
be supplied with larger sizes, to be substituted if circumstances
require it. Two hooks will be ample. One of these should be only a few
inches from the lead, and the other about eighteen or twenty inches
higher. The whole arrangement, known as a Paternoster, is represented in
fig. 33, in which the method of fixing the lead and the hook links is
also illustrated.
[Illustration: FIG. 33.--THE PATERNOSTER]
It will be seen that a swivel has been introduced in connection with the
bottom hook, the object being to show the manner in which this useful
piece of tackle is fitted. It must not be supposed, however, that
swivels are always necessary. It is often useful to insert a swivel on
the line itself, above the Paternoster, when it is of twisted material,
in order to prevent it from kinking; but its use is more frequently
serviceable on the hook links, especially when fishing where the
currents are strong. When the bait used is one that presents two flat
surfaces to the water, as would be the case with a strip of mackerel, a
strong current will set it spinning round and round, thus causing the
hook link to kink if it has not been fitted with a swivel, and the same
effect is often produced by the spinning of a fish on the hook.
The employment of a suitable ground bait will often make a wonderful
difference in the angler’s haul. It frequently attracts large numbers,
keeping them near at hand for some considerable time, and apparently
sharpens their appetite. It may be often observed, too, that a fish will
bite freely at the angler’s bait when in the neighbourhood of the ground
bait, while the former is viewed with suspicion in the absence of the
latter.
When fishing on the bottom only, the ground bait should be weighted if
it is of such a nature that it does not sink readily or if it is liable
to be carried away by currents; but it will often be found more
convenient to secure it on the end of a string, tied up in a muslin bag
if necessary, so that it may be adjusted to any desired depth.
Among the attractive viands suitable for this purpose we may mention
mussels, crushed crabs, pounded liver, the guts of any oily fish, and
the offal of almost any animal.
Along the east coast, and in some of the sandy bays of Devon and
Cornwall, fishing from the beach is practised, but we can hardly
recommend this as of much value to the amateur whose object is to obtain
as great a variety as possible of fishes for study. Some good food
fishes are often caught by this means, but the methods employed are
often very primitive, and would lack all interest to those who love good
sport.
On the east coast a long line, fitted with many hooks, is slung out as
far as possible by means of a pole, and the home end either held in the
hand of the fisher or fastened to the top of a flexible stick driven
into the sand. The latter plan becomes necessary when more than one line
is owned by the same individual, and he is made aware of the bite of a
large fish--and a large fish only, since the hooks are placed beyond a
heavy lead--by the bending of the stick.
The naturalist, however, is as much interested in the small fish as the
large ones, and, even for beach fishing, a rod and line, fitted with one
or two hooks only, and a lead no heavier than is absolutely essential,
will be preferable. A little practice will of course be necessary in
order that one may become expert in the casting of the rod line, but
with large rings on the rod, and a reel without a check, or a check that
can be thrown off when desired, the necessary proficiency in casting
ought to be acquired without much difficulty.
In some of the sandy bays of the south-west, long lines with a heavy
lead at both ends and baited hooks at short intervals throughout the
whole length, are placed on the sand at low tide close to the water’s
edge, and left unwatched until the next tide is out. As far as our
observations go this primitive mode of fishing is usually anything but
successful, the receding of the tide generally revealing a long row of
clean hooks, with, perhaps, one or two dead or half-dead fish; and it is
probable that most of the bait is devoured by crabs and other
crustaceans before the water becomes sufficiently deep to allow the
desired fishes to reach it.
There is one other method of fishing on which we may make a few remarks,
although it hardly comes under the heading of shore fishing. We refer to
a method of catching surface fishes from a moving boat, which method is
known as whiffing. The line is weighted with a lead which must be
regulated according to the speed of the boat. If the boat is an ordinary
rowing-boat, kept going at only a moderate speed, a few ounces of lead
will be sufficient, but a whiffing line trailing behind a sailing boat
travelling in a good breeze will require a pound or two of lead to keep
the bait only a little below the surface.
Beyond the lead we have three or four yards of gimp or strong gut, at
the end of which is a single hook fitted with a spinner, or baited with
some attractive natural or artificial bait. Whatever be the bait used,
there will certainly be more or less spinning caused by the resistance
offered by the water, hence it will be necessary to have a swivel beyond
the lead.
When whiffing near the shore, care must be taken to avoid outlying rocks
that approach the surface of the water, or a sudden snapping of the line
will give you an unwelcome warning of their existence. Further, we
should note that the fishes which are to be caught when whiffing do not
always swim at the same depth, thus it will be advisable to fish at
different distances from the surface by varying either the weight of the
lead or the speed of the boat.
CHAPTER IV
_THE MARINE AQUARIUM_
We have already advised our readers to take home their specimens alive
for the purpose of studying their growth and habits. Now, although there
may be some difficulties in the way of keeping marine animals and plants
alive for any considerable time, yet we are inclined to emphasise the
importance of this matter, knowing that the pleasure and instruction
that may be obtained from even a moderately successful attempt to carry
this out will far more than compensate for the amount of trouble
entailed. There are very many marine objects that are exceedingly pretty
and also very instructive, even when studied apart from the life with
which they were associated in the sea. Thus, a well-preserved sea-weed
may retain much of its original beauty of form and colour, the shells of
numerous molluscs and crustaceans exhibit a most interesting variety of
features well worthy of study, and a number of the soft-bodied animals
may be preserved in such a manner as to closely resemble their living
forms. This being the case, we can hardly say anything to discourage
those who gather sea-side objects merely for the purpose of making a
collection of pretty and interesting things to be observed and admired.
Such objects must necessarily afford much pleasure and instruction, and
the time spent in the collection and preparation will certainly cause
the collector to stray to the haunts of the living things, where he is
certain to acquire, though it may be to a great extent unconsciously, a
certain amount of knowledge concerning their habits and mode of life.
Moreover, sea-side collecting is one of the most healthy and
invigorating of all out-door occupations, and for this reason alone
should be encouraged.
Yet it must be observed that he whose sea-side occupation is merely that
of a collector, and whose work at home is simply the mounting and
arranging of the objects obtained, can hardly be considered a
naturalist. Natural history is a living study, and its devotee is one
who delights in observing the growth and development of living things,
watching their habits, and noting their wonderful adaptation to their
environments; and it is to encourage such observation that we so
strongly recommend the young collector to keep his creatures alive as
far as it is possible to do so.
The first thing to settle, then, is the nature of the vessel or vessels
that are to serve the purpose of aquaria for the work of the young
naturalist.
As long as the outdoor work is in progress temporary aquaria will be
very useful as a means by which the objects collected may be sorted and
stored until a final selection is made for the permanent tank. These
temporary aquaria may consist of jars or earthenware pans of any kind,
each containing a few small tufts of weed, preferably attached to pieces
of rock, and a layer of sand or gravel from the beach.
As such temporary aquaria will, as a rule, be within a convenient
distance from the sea-side where the collecting is being done, there
will be, we presume, no great difficulty in the way of obtaining the
frequent changes of water necessary to keep the animals and plants in a
healthy condition, so that we need do no more now than urge the
importance of avoiding overcrowding, and of renewing the water
frequently for the purpose of supplying the air required for the
respiration of the inmates.
When it is desired to isolate small species in such a manner that their
movements may be conveniently observed, glass jars answer well; but
whatever be the form or size of the vessels used, care must be taken to
avoid excess of both light and heat. They should be kept in a cool
place, quite out of the way of direct sunshine, and the glass vessels
used should be provided with a movable casing of brown paper to exclude
all light except that which penetrates from above.
Even temporary aquaria, used merely for the purpose suggested above,
should be carefully watched, for a single day’s neglect will sometimes
result in the loss of several valuable captives. A dead animal should be
removed as soon as it is discovered to avoid the unpleasant results
arising from the putrefaction of its body. The appearance of a scum or
film on the surface of the water should always be regarded with
suspicion. Such a scum should be removed with the aid of absorbent
paper, since it tends to prevent the absorption of oxygen from the air;
and, should the water be tainted in the slightest degree, it should be
changed at once, or, if this is not practicable, air should be driven
into it for some time by means of a syringe with a very fine nozzle.
Such precautions, however, are not so urgently needed when the aquarium
contains crustaceans only, for the majority of these creatures suffer
less than others in the tainted sea water, some even being apparently
quite as comfortable in this as in a supply fresh from the sea.
Sea-weeds exhibiting the slightest tendency to decay must be removed at
once; and, as regards the feeding of the animals, one must be careful to
introduce only as much food as is required for immediate use, so that
there be no excess of dead organic matter left to putrefy. Some of the
marine animals obtained from our shores feed entirely on the minute and
invisible organisms that are always present in the sea water, and others
subsist principally on certain of the weeds. Many, however, of a more
predaceous disposition, capture and devour living prey, while some, and
more especially the crustaceans, are partial to carrion. If, therefore,
the observer desires to study the ways in which the various creatures
secure and devour their food, he should introduce into his aquaria live
marine worms and other small animals, and also small pieces of fish or
flesh.
We will now pass on to the more serious undertaking of the construction
and management of a permanent salt-water aquarium.
The first point to decide is, perhaps, the size of the proposed vessel,
and this will in many cases be determined partly by a consideration of
the space at one’s disposal, and of the apartment it is intended to
occupy. If it is to be placed in a drawing-room or other ordinary
apartment of a dwelling-house, preference should be given to a window
facing the north in order to avoid the direct rays of the sun, but
perhaps no situation is more suitable than a cool conservatory in the
shady part of a garden; and in either case a strong table or other
support should be provided, of a form and size adapted to those of the
aquarium to be constructed.
Various materials may be used in the construction of such an indoor
aquarium, and we shall deal with two or three different types, so that
the reader may make his selection according to his fancy, or to his
mechanical ability, if he intends that it shall be of his own
construction.
We will begin with an aquarium constructed entirely of a mixture of
cement and fine sand, this being the most inexpensive and certainly the
easiest to make; and although it may not be regarded as the most
ornamental--but opinions will differ on this point--yet it has the
decided advantage of being the nearest approach to the natural rock
pool. Though somewhat heavy and cumbersome, even when empty, the amount
of material used in its construction may be varied according to the
taste and convenience of the maker. Further, this form of aquarium is
one that will readily admit of structural alterations at any future
period. It may be deepened at any time; lateral additions or extensions
may be made, or a portion may at any time be shut off for the purpose of
isolating certain of the animals procured.
[Illustration: FIG. 34.--SECTION OF AN AQUARIUM CONSTRUCTED WITH A
MIXTURE OF CEMENT AND SAND]
The first thing to do is to prepare a flat, strong slab of hard wood or
stone, the exact shape and size of the desired artificial pool, and then
cover this, if of wood, with a mixture of fine sand and cement, mixed to
a convenient consistency with water, to the depth of about one inch. The
banks or walls of the pool must then be built up on all sides, and this
is best done by the gradual addition of soft pellets of cement, applied
in such a manner as to produce an irregular surface. Unless the walls of
the aquarium be very thick and massive the cement will soon show a
tendency to fall from its place as the height increases, but this may be
avoided by doing the work in instalments, allowing each portion to set
before further additions are made to the structure.
Since some marine animals like to occupy snug and shady niches in deep
water while others prefer full exposure to the light in shallows,
arrangements should be made for all by varying the depth of the bed, and
providing several little tunnels and caverns. This may be accomplished
either by working the cement itself into suitable form, or by means of
piled stones obtained from the sea beach; and if the latter plan is
adopted, the stones should not be obtained until the aquarium is quite
ready for its living contents; for then a selection of stones and rock
fragments with weeds, anemones, sponges, and other fixed forms of life
attached to them, may be made. The natural appearance of a rock pool is
thus more nearly approached, and in a shorter time than if the sedentary
life were required to develop on an artificial ground.
Objection may be raised to the form of aquarium just described on the
ground that no life within it is visible except when viewed from above.
But is not this also the case with a rock pool on the sea shore? And has
any admirer of nature ever been heard to complain of the beauties of
such a pool because he was unable to look at them through the sides?
Further, it may be urged that the inmates of our aquarium will be living
under more natural conditions than those of the more popular glass-sided
aquaria, _because_ they receive light from above only.
[Illustration: FIG. 35.--CEMENT AQUARIUM WITH A GLASS PLATE IN FRONT]
However, should the reader require a glass front to his cement tank, the
matter is easily accomplished. Three sides are built up as before
described. A sheet of thick glass--plate glass by preference--is then
cut to the size and shape of the remaining space, and this is fixed by
means of cement pressed well against its edges, both inside and outside.
Water should not be put into the tank until it is quite dry; and, if one
side is made of glass, not until the cement surrounding the edge of the
glass has been liberally painted with marine glue, hot pitch, or some
other suitable waterproof material.
If any pipes are required in connection with the water supply of the
aquarium, according to either of the suggestions in a later portion of
this chapter, such pipes may be fixed in their proper places as the
cement sides are being built up.
The next type of aquarium we have to describe is of low cost as far as
the materials are concerned, and one that may be made by any one who has
had a little experience in woodwork; and although the tank itself is of
a simple rectangular form, yet it may be made to look very pretty with a
suitable adjustment of rocks and weeds.
It consists of a rectangular box, the bottom, ends, and back of which
are of hard wood, firmly dovetailed together, and the front of plate
glass let into grooves in the bottom and ends. All the joints and
grooves are caulked with marine glue, but no paint should be used in the
interior.
This form of tank may be vastly improved by the substitution of slabs of
slate for the wood, though, of course, this change entails a much
greater expenditure of both time and cash; but supposing the work to be
well done, the result is everything that could be desired as far as
strength and durability are concerned.
[Illustration: FIG. 36.--AQUARIUM OF WOOD WITH GLASS FRONT]
In either of the rectangular tanks just described glass may be used for
two sides instead of one only; and since this is not a matter of very
great importance, the choice may well be left to the fancy of the one
who constructs it.
Some prefer an aquarium with glass on all sides, and where this is the
case the framework may be made of angle zinc with all the joints
strongly soldered. Such an aquarium may be made in the form of any
regular polygon, for it is no more difficult to construct one of six or
eight sides than of four. It is more difficult, however, to make such an
aquarium perfectly watertight, for the glass, instead of being in
grooves, has to be securely fastened to the metal frame by means of a
cement on one side only, and this cement has to serve the double purpose
of holding the glass and keeping in the water.
Various mixtures have been suggested for this purpose, and among them
the following are perfectly satisfactory:--
1. Litharge 2 parts
Fine sand 2 "
Plaster of Paris 2 "
Powdered resin 1 part
Mix into a very thick paste with boiled linseed oil and a little driers.
2. Red lead 3 parts
Fine sand 3 ”
Powdered resin 1 part
Mix with boiled linseed oil as above.
Both these cements should be applied very liberally, and the aquarium
then allowed to remain quite undisturbed for at least two weeks before
any water is introduced.
[Illustration: FIG. 37.--HEXAGONAL AQUARIUM CONSTRUCTED OF ANGLE ZINC,
WITH GLASS SIDES]
When ready for the water, the bottom of the aquarium should be covered
with a moderately thick layer of fine sand from the sea shore, and
stones then piled in such a manner as to form little tunnels and caves
to serve as hiding-places for those creatures that prefer to be under
cover. As to the selection of stones, we have already suggested that
some may have weeds rooted to them, and that pieces of rock with
anemones, sponges, and other forms of life attached may be chipped off.
Further, on many of our rocky coasts we may find, near low-water mark, a
number of stones covered with a layer of vegetable growth, amongst which
many small animals live, often more or less concealed by their
protective colouring. Some of these stones placed on the bed of the
salt-water aquarium would add greatly to the natural appearance, as well
as give greater variety to the living objects. Shells bearing the
calcareous, snakelike tubes of the common serpula (p. 121), preferably
with the living animals enclosed, will also enhance the general
appearance and interest of the aquarium.
In making preparations previous to the introduction of animal life, due
regard should be paid to the peculiar requirements of the creatures it
is intended to obtain. We have already referred to the advisability of
arranging the bed of the tank in such a manner that the water may vary
considerably in depth, so that both deep and shallow water may be found
by the animals as required, and to the provision of dark holes for
crustaceans and other creatures that shun the light. Very fine sand
should be provided for shrimps, prawns, and other animals that like to
lie on it; and this sand must be deep in places if it is intended to
introduce any of the burrowing molluscs and marine worms.
The water used may be taken from the sea or be artificially prepared.
The former is certainly to be preferred whenever it can be conveniently
obtained, and at the present time few will find much difficulty in
securing a supply, for not only are we favoured with the means of
obtaining any desired quantity by rail at a cheap rate from almost any
seaport, but there are companies in various ports who undertake the
supply of sea water to any part of the kingdom. If the water is to be
conveyed from the coast without the aid of the regular dealers in this
commodity, great care must be taken to see that the barrel or other
receptacle used for the purpose is perfectly clean. Nothing is more
convenient than an ordinary beer or wine barrel, but it should be
previously cleansed by filling it several times with water--not
necessarily sea water--and allowing each refill to remain in it some
time before emptying. This must be repeated as long as the water shows
the slightest colouration after standing for some time in the barrel.
Should any difficulty arise in the way of getting the salt water direct
from the sea, it may be made artificially by dissolving ‘sea salt’ in
the proper proportion of fresh water, or even by purchasing the
different salts contained in the sea separately, and then adding them to
fresh water in proportionate quantities.
The composition of sea water is as follows:--
Water 96·47 per cent.
Sodium chloride 2·70 ”
Magnesium chloride ·36 ”
Magnesium sulphate (Epsom salts) ·23 ”
Calcium sulphate ·14 ”
Potassium chloride ·07 ”
Traces of other substances ·03 ”
100·00
and it will be seen from this table that artificial sea water may be
made by adding about three and a half pounds of sea salt, obtained from
the sea by the simple process of evaporation, to every ninety-six and a
half pounds of fresh water used. In making it there may be some
difficulty in determining the weight of the large volume of water
required to fill an aquarium of moderate dimensions, but this will
probably disappear if it be remembered that one gallon of water weighs
just ten pounds, and, therefore, one pint weighs twenty ounces.
If the sea salt cannot be readily obtained, the following mixture may be
made, the different salts being purchased separately:--
Water 96-1/2 lbs.
Sodium chloride (common salt) 43-1/4 ozs.
Magnesium chloride 5-3/4 ”
Epsom salts 3-3/4 ”
Powdered gypsum (calcium sulphate) 2-1/4 ”
Although in this mixture the substances contained in the sea in very
small quantities have been entirely omitted, yet it will answer its
purpose apparently as well as the artificial sea water prepared from the
true sea salt, and may therefore be used whenever neither sea salt nor
the natural sea water is procurable.
Assuming, now, that the aquarium has been filled with sea water, it
remains to introduce the animal and vegetable life for which it is
intended; and here it will be necessary to say something with regard to
the amount of life that may be safely installed, and the main conditions
that determine the proportion in which the animal and vegetable life
should be present in order to insure the greatest success.
Concerning the first of these we must caution the reader against the
common error of overcrowding the aquarium with animals. It must be
remembered that almost all marine animals obtain the oxygen gas required
for purposes of respiration from the air dissolved in the water. Now,
atmospheric air is only very slightly soluble in water, and hence we can
never have an abundant supply in the water of an aquarium at any one
time. If a number of animals be placed in any ordinary indoor aquarium,
they very soon use up the dissolved oxygen; and, if no means have been
taken to replace the loss, the animals die, and their dead bodies soon
begin to putrefy and saturate the water with the poisonous products of
decomposition.
It is probably well known to the reader that a large proportion of the
oxygen absorbed by the respiratory organs of animals is converted by
combination of carbon into carbonic acid gas within their bodies, and
that this gas is given back into the water where it dissolves, thus
taking the place of the oxygen used in its formation.
If, then, an aquarium of any kind is to be a success, some means must be
taken to keep the water constantly supplied with fresh oxygen quite as
rapidly as it is consumed, and this can be done satisfactorily by the
introduction of a proportionate quantity of suitable living weeds,
providing there is not too much animal life present.
The majority of living plants require carbonic acid gas as a food, and,
under the influence of light, decompose this gas, liberating the oxygen
it contained. This is true of many of our common sea-weeds, and thus it
is possible to establish in a salt-water aquarium such a balance of
animal and vegetable life that the water is maintained in its normal
condition, the carbonic acid gas being absorbed by the plants as fast as
it is excreted by animals, and oxygen supplied by the plants as rapidly
as it is consumed by the animals.
This condition, however, is more difficult to obtain in a salt-water
aquarium than in one containing fresh-water life, partly because,
generally speaking, the sea-weeds do not supply oxygen to the water as
rapidly as do the plants of our ponds and streams, and partly because of
the difficulties attending the successful growth of sea-weeds in
artificial aquaria. Thus it is usually necessary to adopt some means of
mechanically aërating the water; but, for the present, we shall consider
the sea-weeds only, leaving the mechanical methods of aërating the water
for a later portion of this chapter.
In the first place, let us advise the amateur to confine his attention
to the smaller species of weeds that are commonly found in small and
shallow rock pools, for the successful growth of the larger purple and
olive weeds will probably be beyond his power, even though his tank be
one of considerable capacity. The best plan is that we have already
suggested--namely, to chip off small pieces of rock with tufts of weed
attached, and to fix them amongst the rockery of the aquarium, being
careful to place those that grew in shallow water with full exposure to
the light, and those which occupied sheltered and shady places in the
rock pool, respectively, in similar situations in the artificial pool.
For the purposes of aëration we have to rely principally on the bright
green weeds, and preference should be given to any of these that
exhibit, in their natural habitat, a multitude of minute air-bubbles on
the surface of their fronds, for the bubbles consist principally of
oxygen that is being liberated by the plant, and denote that the species
in question are those that are most valuable for maintaining the desired
condition of the water in an aquarium.
Any small sea-weed may be tried at first, but experience will soon show
that some are much more easily kept alive than others. In this
experimental stage, however, a constant watch should be maintained for
the purpose of detecting signs of decay in the marine garden. A plant
should always be removed as soon as it presents any change from the
natural colour, or exhibits the smallest amount of slimy growths on the
surface, for decomposing plants, as well as decaying animals, will soon
convert an aquarium into a vessel of putrid and poisonous water.
It seems almost unnecessary to name a selection of sea-weeds for small
aquaria, seeing that our rock pools produce so many extremely beautiful
species, most of which may be successfully kept alive in a well-managed
tank; but the common Sea Grass (_Enteromorpha compressa_), and the Sea
Lettuce (_Ulva latissima_), also known locally as the Green Laver or
Sloke, are particularly useful for the aëration of the water; while the
Common Coralline (_Corallina officinalis_), the Dulse (_Schizymenia
edulis_), the Peacock’s tail (Padina pavonia), the Irish or Carrageen
Moss (_Chondrus crispus_), _Callithamnion_, _Griffithsia setacea_,
_Plocamium plumosium_, _Rhodymenia palmata_, _Rhodophyllis bifida_, and
_Ceramium rubrum_ are all beautiful plants that ought to give no trouble
to the aquarium-keeper.
It is not advisable to introduce animal life into the aquarium
immediately it is filled, on account of the possibility of the water
being contaminated by contact with the cement that has been used to make
it water-tight. It is safer to allow the first water to stand for a few
weeks, the weeds and all other objects being _in situ_, and the
necessary means employed for perfect aëration during this interval, and
then, immediately before the animals are placed in their new home, to
syphon off the whole of the water, and refill with a fresh supply.
In the selection of animals due regard should be paid to two important
points--first, the danger of overcrowding, and, secondly, the
destructive habits of some of the more predaceous species.
No more than two or three animals should, as a rule, be reckoned for
each gallon of water; and the proportion of animals should be even less
than this when any of them are of considerable size.
As regards the destructive species, these are intended to include both
those that are voracious vegetable feeders and also those whose habit it
is to kill and prey on other creatures.
It must be understood that the weeds are to serve two distinct
purposes:--They are to supply at least some of the oxygen required for
the respiration of the animal inmates, and also to serve as food for
them. Some marine fishes and molluscs feed on the fronds of the weeds,
and among these the common periwinkle may be mentioned as one of the
most voracious. If many such animals are housed in the aquarium, it will
be necessary to replace at intervals those species of weeds that suffer
most from their ravages. The zoospores thrown off by the weeds,
particularly in the autumn, are also valuable as food for some of the
animals.
Notwithstanding the destructive character of the periwinkle just
referred to, it has one redeeming feature, for it is certainly useful in
the aquarium as a scavenger, as it greedily devours the low forms of
vegetable life that cover the glass and rocks, thus helping to keep them
clean; and the same is true of the common limpet and other creeping
molluscs. Some of these are even more to be valued on account of their
partiality for _decaying_ vegetable matter, by devouring which they
reduce the amount of the products of decomposition passing into the
water.
Other details concerning the selection of animal and vegetable life for
the indoor aquarium must be left to the discretion and experience of the
keeper, for it is impossible by written instructions and advice to cover
all the various sources of loss and trouble that may from time to time
arise. If, however, the general hints for the management of the marine
aquarium here given be faithfully followed, there ought to be no further
losses than must accrue from the injudicious selection of animal
species, and these will decrease as experience has been acquired
respecting the habits of the creatures introduced.
We must now pass on to matters pertaining to the maintenance of the
healthy condition of an aquarium which, we will suppose, has been
established with due regard to scientific principles. Under this head we
shall consider, (1) the aëration of the water, (2) the repair of loss
due to evaporation, and (3) the regulation of light and temperature.
It has already been shown that the marine aquarium can hardly be
maintained in a satisfactory condition as regards its air supply by
leaving the aëration of the water entirely to the action of plant life;
and herein this form of aquarium differs from that employed for the
animal and vegetable life derived from ponds and streams. Fresh-water
weeds develop and multiply with such rapidity, and are such ready
generators of oxygen gas that it is a very easy matter to establish a
fresh-water aquarium that will remain in good condition for years with
but little attention; it is therefore important that we should point out
the difference in treatment necessary to those of our readers who are
already acquainted with the comparative ease with which the fresh-water
aquarium may be kept in good order, lest they expect the same
self-aërating condition in the marine tank.
It is never a good plan to leave the renovation of the water of the
aquarium until there are visible signs within that something is going
wrong. It is true that an unsatisfactory condition of the water,
revealed by a slight taint in the odour, or a general turbidity, or the
formation of a slight scum on the surface, may sometimes be rectified by
the prompt application of some method of artificial aëration, but the
aim of the aquarium-keeper should be not the rectification of
unsatisfactory conditions, but the establishment of such a method of
aëration that the unsatisfactory condition becomes an impossibility. We
do not wish to discourage anyone who has the slightest desire to start a
marine aquarium. Our aim is to point out any difficulties that lie in
the way in order that the aquarium may be a success; and thus, having
stated that the difficulties attending it are somewhat greater than
those connected with the management of a fresh-water aquarium, we should
like to add that these practically disappear when one is prepared to
devote a short time at regular intervals in order to see that the
process of aëration is properly carried out.
Some recommend the occasional injection of air by a syringe as one means
of aërating the water; but, although this may be all very well as a
_temporary_ purifier of the slightly tainted aquarium, it is hardly
suitable as a means of maintaining a good, healthy condition. It must be
remembered that oxygen gas--the gas of the atmosphere so essential to
animal life--is only very slightly soluble in water. By this we mean not
only that water dissolves oxygen very slowly, but also that it can never
hold a large supply of the gas at any one time. This being the case, it
is clear that the use of a syringe for a short time, though it
discharges an enormous total volume of air into the water, will result
in the actual solution of only a small quantity. No method of aëration
is perfect that allows the admission of air for a short time only at
comparatively long intervals; the most perfect system is that in which
air is slowly but _continuously_ passed into solution.
Since air is slightly soluble in water, it is clear that it must be
continuously passing into any body of water that has its surface freely
exposed to it; hence a wide and shallow aquarium is much more likely to
keep in good order than one that is narrower and deeper. But, with
marine aquaria, the simple absorption from the air at the surface is not
in itself sufficient, as a rule, to maintain a healthy condition. Yet it
will be advisable to remember this matter when constructing a tank for
marine life.
One of the prettiest, and certainly one of the most effectual, methods
of supplying air to an aquarium is by means of a small fountain with a
very fine spray. The water need seldom be changed, but the fountain may
be fed by water from the aquarium, and as the fine spray passes through
the air it will absorb oxygen and carry it in solution to the tank.
The accompanying diagram illustrates the manner in which this can be
accomplished. The aquarium (A) is supplied with an outlet (O) about an
inch from the top by means of which the water is prevented from
overflowing, and the outlet pipe leads to a vessel (V) of considerable
capacity which, for the sake of convenience and appearance, may be
concealed beneath the table on which the aquarium stands. Some feet
above the level of the aquarium is another vessel (C), supported on a
shelf, having about the same capacity as V, and supplied with a small
compo pipe that passes down into the aquarium, and then, hidden as much
as possible by the rockery, terminates in a very fine jet just above the
level of the water in the centre. The upper vessel should also be
provided at the top with a loose covering of muslin to serve as a
strainer, and this should be replaced at intervals as it becomes clogged
with sedimentary matter.
In order that this arrangement may give perfect satisfaction the two
vessels (C and V) must each be of at least half the capacity of the
aquarium itself, and the total quantity of salt water sufficient to fill
the aquarium together with one of them. It should also be remembered
that since the pressure of water depends not on its quantity, but on its
height measured perpendicularly, it follows that the height to which the
fountain will play is determined by the height of the vessel C above the
level of the jet.
[Illustration: FIG. 38.--METHOD OF AËRATING THE WATER OF AN AQUARIUM
A, aquarium with fountain; C, cistern to supply the fountain;
O, pipe for overflow; V, vessel for overflow]
Let us now suppose that the aquarium and the upper vessel have both been
filled with sea water. The fine jet from the pipe plays into the air and
returns with a supply of oxygen to the aquarium, while the excess above
the level of O passes into the concealed vessel below the table. If the
two vessels are as large as we recommend, and the jet a very fine one,
the fountain may continue to play for hours before C is empty, the
animals of the tank being favoured all this time with a continuous
supply of air. And when the supply from above is exhausted, the contents
of the bottom vessel are transferred to the top one, and at the same
time so effectually strained by the layer of muslin that no sedimentary
matter passes down to choke the fine jet of the fountain. One great
advantage this method possesses is that the living creatures derive the
benefit of a much larger quantity of water than the aquarium alone could
contain; and thus, apart from the aërating effects of the fountain, the
result is the same as if a much larger tank were employed.
In our next illustration (fig. 39) we give a modified arrangement based
on the same principle which may commend itself by preference to some of
our readers. Here the supply pipe to the fountain passes through a hole
in the bottom of the aquarium instead of into the top, and the outlet
pipe is bent downward within so as to form a syphon.
Those who are acquainted with the principle of the syphon will
understand at once the working of such an arrangement as this. Let us
suppose the vessel _c_ to be full of water, and the fountain started,
while the water in the aquarium stands no higher than the level _l_. The
water slowly rises until the level _h_ of the bend of the outlet tube
has been reached, and during the whole of this time no water escapes
through the exit. As soon, however, as the latter level has been
attained, the water flows away into the lower vessel, into which it
continues to run until the lower level is reached, and then the outflow
ceases, not to commence again until the fountain causes the water to
rise to the upper level.
From what has been said the reader will see that the total quantity of
water required in this instance need not exceed the capacity of the
aquarium; also that each of the vessels connected with water supply and
waste should have a capacity equivalent to the volume of water contained
in the aquarium between the two levels _h_ and _l_.
The alternate rising and falling of the water produced in the manner
just described represents in miniature the flow and ebb of the tides,
but perhaps this is in itself of no great advantage in the aquarium
except from the fact that it allows those creatures that prefer to be
occasionally out of the water for a time a better opportunity of
indulging in such a habit. And further, with regard to both the
arrangements for aëration above described, it should be noted that
earthenware vessels are much to be preferred to those made of metal for
the holding of sea water, since the dissolved salts corrode metallic
substances rather rapidly, and often produce, by their chemical action,
soluble products that render the water more or less poisonous.
[Illustration: FIG. 39.--AQUARIUM FITTED WITH APPARATUS FOR PERIODIC
OUTFLOW]
Other methods of aërating the water of aquaria are practised, but these,
as a rule, are only practicable in the case of the large tanks of public
aquaria and biological laboratories, as the mechanical appliances
necessary to carry them out successfully are beyond the means of an
ordinary amateur.
In such large tanks as those referred to it is common to force a fine
jet of air into the water by machinery. Sometimes this air is driven
downward from a jet just below the surface, and with such force that a
multitude of minute bubbles penetrate to a considerable depth before
they commence to rise, but in others the air is made to enter at the
bottom and must therefore pass right through the water.
Of course the amateur aquarium-keeper may carry out this method of
aëration with every hope of success providing he has some self-acting
apparatus for the purpose, or can depend on being able himself to attend
to a non-automatic arrangement at fairly regular intervals, always
remembering that a single day’s neglect, especially in the case of a
small tank with a proportionately large amount of animal life, may lead
to a loss of valuable specimens.
We have already mentioned the use of a syringe as a means by which an
aquarium may be temporarily restored to a satisfactory condition
providing it has not been neglected too long, and some recommend forcing
air, or, still better, pure oxygen gas, from an india-rubber bag into
the water. We have used, for the same purpose, a stream of oxygen from a
steel cylinder of the compressed gas with very satisfactory results; and
since oxygen may be now obtained, ready compressed, at a very low
price--about twopence a cubic foot--there is much to be said in favour
of this method as an auxiliary in the hands of the owner of a small
tank, though we hardly recommend it as a prime means of aëration to take
the place of the fountain.
In any case, where a stream of air or oxygen is employed, an exceedingly
fine jet should be used, in order that the expelled gas may take the
form of a stream of minute bubbles; for, as previously stated, the water
can absorb the gas only very slowly, so that there must necessarily be a
considerable waste when the gas issues rapidly. Further, the smaller the
bubbles passing through the water, the greater is the total surface of
gas in contact with the liquid, the volume of the supply being the same,
and hence the more effectually will the solution of the gas proceed.
Again, another advantage of the fine stream of minute bubbles lies in
the fact that the smaller these bubbles are the more slowly they rise to
the surface of the water, and thus the longer is the time in which the
gas may be absorbed during its ascent.
A fine jet, well suited to the purpose here defined, may be made very
easily by holding the middle of a piece of glass tubing in a gas flame
until it is _very_ soft, and then, immediately on removing it, pulling
it out rather quickly. A slight cut made with a small triangular file
will then enable the operator to sever the tube at any desired point.
Yet another method of maintaining the air supply of aquaria is adopted
in the case of some of the large tanks of public aquaria and biological
laboratories situated close to the sea, and this consists in renewing
the water at every high tide by means of pumps.
It must not be supposed that an indoor aquarium, even when well
established, and supplied with the best possible system of aëration,
requires no further care and attention. In the first place there is a
continual loss of water by evaporation, especially in warm and dry
weather, and this must be rectified occasionally. Now, when water
containing salts in solution evaporates, the water passing away into the
air is perfectly free from the saline matter, and thus the percentage of
salt in the residue becomes higher than before. It is evident,
therefore, that the loss by evaporation in a marine aquarium must be
replaced by the addition of _fresh_ water, which should either be
distilled, or from the domestic supply, providing it is soft and
moderately free from dissolved material.
But the question may be asked, ‘Do not the marine animals and plants
utilise a certain amount of the saline matter contained in the salt
water?’ The answer to this is certainly in the affirmative, for all
sea-weeds require and abstract small proportions of certain salts, the
nature of which varies considerably in the case of different species;
and, further, all the shelled crustaceans and molluscs require the salts
of lime for the development of their external coverings, and fishes for
the growth of their bony skeletons. Hence the above suggestion as to the
replenishment of loss by evaporation with pure water is not perfectly
satisfactory. It will answer quite satisfactorily, however, providing
the sea water is _occasionally_ changed for an entirely new supply.
Again, since carbonate of lime is removed from sea water more than any
other salt, being such an essential constituent of both the external and
internal skeletons of so many marine animals, as well as of the
calcareous framework of the coralline weeds, we suggest that the
aquarium may always contain a clean piece of some variety of carbonate
of lime, such as chalk, limestone, or marble, which will slowly dissolve
and replace that which has been absorbed.
Water is rendered denser, and consequently more buoyant, by the presence
of dissolved salts; and, since the density increases with the proportion
of dissolved material, we are enabled to determine the degree of
salinity by finding the density of the solution. We can apply this
principle to the aquarium, as a means of determining whether the water
contains the correct amount of sea salt, also for testing any artificial
salt water that has been prepared for the aquarium.
Probably some of our readers are acquainted with some form of
hydrometer--an instrument used for finding the density of any liquid;
but we will describe a simple substitute that may be of use to the owner
of a marine aquarium, especially if the salt water for the same is
artificially prepared. Melt a little bees-wax, and mix it with fine,
clean sand. Then, remembering that the wax is lighter than water, and
consequently floats, while sand is considerably heavier, and sinks,
adjust the above mixture until a solid ball of it is just heavy enough
to sink _very slowly_ in sea water. Now make two such balls, and then
cover one of them with a light coating of pure wax. We have now two
balls, one of which will float in sea water, and the other sink, and
these may be used at any time to test the density of the water in, or
prepared for, the aquarium. If the water is only a little too salt, both
balls will float; while, if not sufficiently rich in saline matter, both
will sink.
We must conclude this chapter by making a few remarks on the important
matter of the regulation of light and temperature. Direct sunlight
should always be avoided, except for short and occasional intervals, not
only because it is liable to raise the temperature to a higher degree
than is suitable for the inmates of the aquarium, but also because an
excess of light and heat tends to produce a rapid decomposition of
organic matter, and a consequent putrid condition of the water, and this
dangerous state is most likely to occur when both light and temperature
are high at the same time.
The water should always be cold; and as it is not always easy to
estimate the temperature, even approximately, by the sensation produced
on immersing the fingers, it is a good plan to have a small thermometer
always at hand, or placed permanently in the aquarium. In the summer
time the water should be kept down to fifty-five degrees or lower, and
in winter should never be allowed to cool much below forty. There may be
some difficulty in maintaining a temperature sufficiently low in summer,
but a small piece of ice thrown in occasionally to replace the loss due
to evaporation, especially on very hot days, will help to keep it down.
CHAPTER V
_THE PRESERVATION OF MARINE OBJECTS_
The sea-side naturalist, in the course of his ramblings and searchings
on the coast, will certainly come across many objects, dead or alive,
that he will desire to set aside for future study or identification in
his leisure moments at home. Some of these will be required for
temporary purposes only, while, most probably, a large proportion will
be retained permanently for the establishment of a private museum, that
shall serve not only as a pleasant reminder of the many enjoyable hours
spent on the shore, but also as a means of reference for the study of
the classification of natural objects and of their distribution and
habitats.
We will first deal with those specimens that are required for temporary
purposes only--those of which the collector desires to study the general
characters, as well as, perhaps, something of the internal structure;
but before doing so we cannot refrain from impressing on the reader the
advisability of learning as much as possible of the external features
and mode of growth of the different living creatures while still alive,
for it must be remembered that it is impossible to preserve many of them
without more or less destruction of their natural colouring and
distortion of their characteristic forms.
In those cases where it is possible to keep the creatures alive for a
short time only, it is a good plan to make notes of their movements and
all observed changes in form, and their methods of feeding, and also to
illustrate these notes by sketches drawn from life. This may seem quite
an unnecessary procedure to many beginners in the study of natural
objects, and may even, as far as the sketches are concerned, present
difficulties that at first appear to be insurmountable; but the power to
sketch from nature will surely be acquired to a greater or less degree
by constant practice, and illustrated notes prepared for the purpose we
suggest will undoubtedly be of great value to the student. Further,
though it may often be necessary to set specimens aside in a
preservative fluid until one has the leisure to examine their structure,
it should always be remembered that they never improve by keeping, also
that they are rarely in such good condition for dissection after
saturation with the preservative as when perfectly fresh.
One of the most convenient preservatives for general use is undoubtedly
methylated spirit. This is alcohol that has been adulterated in order to
render it undrinkable, so that it may be sold free from duty for use in
the various arts and manufactures without any danger of its being
employed for the concoction of beverages. It may be used just as
purchased--that is, in its strongest condition--for many purposes, but
in this state it has a powerful affinity for water, and will rapidly
abstract water from animal and vegetable objects, causing the softer
ones to become hard, shrunken, and shrivelled, often to such an extent
that they are almost beyond recognition.
By diluting the spirit, however, we satisfy to a great extent its
affinity for water, and thus prevent, or, at least, reduce the action
just mentioned. A mixture of equal quantities of spirit and water is
quite strong enough. Unfortunately the common methylated spirit of the
shops produces a fine white precipitate, that gives the whole mass a
milky appearance, when it is diluted. This is due to the presence of
mineral naphtha, which is added in a certain fixed proportion in
accordance with the Government regulations. But it _is_ possible, by
special application, to obtain the ‘non-mineralised’ or ‘ordinary’
methylated spirit of former years, though not in small quantities, and
this liquid dissolves in water without the formation of a precipitate.
It should be noted, however, that the use of the spirit as a
preservative is in no way interfered with by the presence of the mineral
naphtha, the only disadvantage of this impurity lying in the fact that
the milkiness consequent on dilution prevents the objects in a specimen
jar from being observed without removal.
We have just referred to the hardening action of strong spirit as a
disadvantage, and so it is when it is required to preserve soft
structures with as little as possible of change in general form and
appearance; but there are times when it becomes necessary to harden
these soft structures in order that sections may be made for the purpose
of examining internal structure with or without the aid of the
microscope, and for such purposes strong spirit is one of the best
hardening agents that can be employed.
Formaldehyde is another very good preservative. It is a colourless
liquid, and should be considerably diluted for use, a two per cent.
solution being quite strong enough for all ordinary purposes. It
possesses some distinct advantages as compared with spirit. In the first
place, it does not destroy the natural colours of objects to the extent
that spirit does; and, although a hardening agent as well as a
preservative, it does not harden soft structures by the extraction of
the water they contain, and therefore does not cause them to become
shrivelled or otherwise distorted. It will also occur to the reader
that, since a small bulk of formaline represents a large volume of the
diluted preservative, it is very conveniently stored, and a very small
bottle of it taken for outdoor work may, on dilution with water, be made
to yield all that is required for the preservation of the takings of a
successful day, or even of a longer period. Formaldehyde is usually sold
in solution of about forty per cent. strength, and for the preparation
of a two per cent. solution it will be found convenient to provide a
glass measure graduated either into cubic centimetres or fluid ounces
and drams. One hundred volumes of the original solution contain forty of
pure formaldehyde, and if water be added to make this up to two thousand
volumes, a two per cent. solution is obtained. Thus, one hundred cubic
centimetres of the original solution is sufficient to prepare two litres
(three and a half pints) of suitable preservative.
A very good preservative liquid may be made by dissolving two ounces of
common salt, one ounce of alum, and two or three grains of corrosive
sublimate (a deadly poison) in one quart of water, and then, after
allowing all sedimentary matter to settle to the bottom, decanting off
the clear solution. This mixture is known as <i>Goadby’s fluid</i>, and is
well adapted for the preservation of both animal and vegetable
structures. It does not cause any undue contraction of soft tissues,
and, as a rule, does not destroy the natural colours of the objects kept
in it.
Glycerine is valuable as a preservative for both animal and vegetable
objects, and especially for the soft-bodied marine animals that form
such a large percentage of the fauna of our shores. It maintains the
tissues in a soft condition, and preserves the natural tints as well as
any liquid.
An inexpensive preservative may also be made by dissolving chloride of
zinc--about one ounce to the pint of water. This is considered by some
to be one of the best fluids for keeping animal structures in good
condition.
Now, although the different fluids here mentioned are described in
connection with the _temporary_ preservation of natural objects, it must
be remembered that they are equally adapted for the permanent
preservation of the animals and plants that are to figure in the museum
of the sea-side naturalist; and, although some marine objects may be
preserved in a dry state in a manner to be hereafter described, yet
there are many species of animals, and also some plants, that can be
satisfactorily preserved only by immersion in a suitable fluid.
This method may be applied to all soft-bodied animals, such as anemones,
jelly-fishes, marine worms, shell-less molluscs (sea slugs, cephalopods,
&c.), the soft parts of shelled molluscs, fishes, &c.; and most sponges
retain their natural appearance much better in a preservative fluid than
in a dry condition. Many sea-weeds also, which are practically destroyed
by the most careful drying process, are most perfectly preserved in
fluid.
But the puzzled amateur will probably be inclined to ask: ‘Which is the
best preservative liquid for this or that specimen?’ No satisfactory
general rule can be given in answer to such a question, and a great deal
will have to be determined by his own experiments and observations.
Whenever he has two or three specimens of the same object, as many
different fluids should be employed, and the results compared and noted.
In this way a very great deal of useful information will be obtained and
by the best possible means. However, it may be mentioned that all the
fluids alluded to above may be safely used for almost every animal or
vegetable specimen with the following reservations: strong spirit should
not be employed for _any_ very soft animal, nor should it be used for
delicate green plants, since it will dissolve out the green colouring
matter (_chlorophyll_), leaving them white or almost colourless.
Further, the greatest care should be exercised in dealing with sea
anemones and jelly-fishes. If spirit is used for preserving these
creatures, it should be very dilute, at least at first, but may with
advantage be increased in strength afterwards, though this should be
done gradually.
Whatever be the preservative used, it is sure to be more or less charged
with sedimentary and coloured matter extracted from the object immersed
in it; hence, if the specimen concerned is to form part of a museum
collection, it will be necessary to transfer it to a fresh solution
after a time, and a second, and even further changes may be necessary
before the object ceases to discolour the fluid or render it turbid.
Considerable difficulty will sometimes be found in the attempts to
preserve a soft-bodied animal in its natural attitude. Thus, when a sea
anemone is removed from its native element, it generally withdraws its
tentacles, and, contracting the upper part of its cylindrical body,
entirely conceals these appendages, together with the mouth they
surround; and a mollusc similarly treated will generally pull itself
together within its shell, leaving little or no trace of the living body
inhabiting the lifeless case. Then, if these animals are transferred to
any fluid other than sea water, or placed anywhere under unnatural
conditions, they usually remain in their closed or unexpanded form.
Thus, almost every attempt to kill them for preservation deprives them
of just the characteristics they should retain as museum specimens.
Some such animals may be dealt with satisfactorily as follows: Transfer
them to a vessel of fresh sea water, and leave them perfectly
undisturbed until they assume the desired form or attitude. Then add a
_solution_ of corrosive sublimate very gradually--a drop or two at
intervals of some minutes. In this way the bodies of anemones may be
obtained ready for preservation with expanded tentacles, tube-secreting
worms with their heads and slender processes protruding from their limy
or sandy cases, molluscs with their ‘feet’ or their mantles and gills
protruding from their shells, and barnacles with their plume-like
appendages projecting beyond the opening of their conical shells.
The specimens thus prepared may be placed at first in very dilute
spirit, and then, after a time, finally stored in a stronger solution of
spirit in water; or they may be transferred to one of the other
preservative solutions previously mentioned.
All specimens permanently preserved in fluid for a museum should be
placed in jars, bottles, or tubes of suitable size, each vessel
containing, as a rule, only one. Where expense is no object, stoppered
jars made expressly for biological and anatomical specimens may be used
for all but the smallest objects; or, failing this, ordinary
wide-mouthed bottles of white glass, fitted with good corks or glass
stoppers.
For very small specimens nothing is more suitable than glass tubes, but
it must be remembered that wherever corks are used, even if they are of
the best quality procurable, it will be necessary to look over the
specimens occasionally to see if the preserving fluid has disappeared to
any extent either by leakage or evaporation; for such loss is always
liable to occur, although it may be very slow, and especially when
methylated spirit is the liquid employed.
[Illustration: FIG. 40.--JARS FOR PRESERVING ANATOMICAL AND BIOLOGICAL
SPECIMENS]
The writer has preserved many hundreds of small marine and other objects
in glass tubes of dilute spirit that have been hermetically sealed, thus
rendering the slightest loss absolutely impossible, while the perfect
exclusion of air prevents the development of fungoid growths that
sometimes make their appearance in imperfectly preserved specimens. The
making and closing of such tubes, though a more or less difficult
operation at first to those who have had no previous experience in
glass-working, become exceedingly simple after a little practice; and
believing it probable that many of our readers would like to try their
hand at this most perfect method of preserving and protecting small
objects, we will give a description of the manner in which it is done.
The apparatus and materials required for this work are:--Lengths of
‘soft’ glass tubing, varying from about one quarter to a little over
half an inch in internal diameter; a supply of diluted spirit--about
half spirit and half water; a Herapath blowpipe, preferably with
foot-bellows; and a small triangular file.
The glass tubing may be cut into convenient lengths by giving a single
sharp stroke with the file, and then pulling it apart with, at the same
time, a slight bending _from_ the cut made.
[Illustration: FIG. 41.--SHOWING THE DIFFERENT STAGES IN THE MAKING OF
A SMALL SPECIMEN TUBE]
Cut a piece of tubing about eight or nine inches long, heat it in the
blowpipe flame, turning it round and round all the time, until it is
quite soft, then remove it from the flame and immediately pull it out
_slowly_ until the diameter in the middle is reduced to about a
sixteenth of an inch (fig. 41, 2). Make a slight scratch with the file
at the narrowest part, and divide the tube at this point (fig. 41, 3).
Now heat one of these pieces of tubing as before just at the point where
the diameter of the drawn part begins to decrease; and, when very soft,
pull it out rather quickly while it is _still in the flame_. The part
pulled now becomes completely separated, and the tube is closed, but
pointed. Continue to heat the closed end, directing the flame to the
point rather than to the sides, until the melted glass forms a rather
thick and flattened end; and then, immediately on removing it from the
flame, blow gently into the open end until the melted glass is nicely
rounded like the bottom of a test-tube (fig. 41, 4). When the tube is
cold, the specimen that it is to contain, and which has already been
stored for a time in dilute spirit, is dropped into it. The tube is now
heated about an inch above the top of the specimen, drawn out as shown
in fig. 41, 5, and again allowed to cool. When cold, the fresh spirit is
poured into the open end of the tube, but the middle part is so narrow
that the spirit will not run down freely. If, however, suction be
applied to the open end, air from the bottom will bubble through the
spirit, and then, on the cessation of the suction, the spirit will pass
down to take the place of the air that was withdrawn. This may be
repeated if necessary to entirely cover the specimen with the fluid. Any
excess of spirit is then thrown from the upper part of the tube, and the
latter cut off. Nothing is now left but to close the tube hermetically.
This is done by heating the lower part of the narrow neck, and then
drawing it out _in the flame_, taking great care that the tube is
withdrawn from the flame the moment it is closed. The tube must also be
kept in an upright position until it has cooled. The appearance of the
finished tube is shown in fig. 41, 6.
[Illustration: FIG. 42.--SMALL SPECIMEN TUBE MOUNTED ON A CARD]
All preserved specimens should have a label attached on which is written
the name of the specimen, the class and order to which it belongs, the
locality in which it was found, together with any brief remarks that the
owner desires to remember concerning its habits &c.
The bottles or tubes that are too small to have a label attached to them
in the ordinary way may be mounted on a card, as represented in fig. 42,
and the desired particulars then written on the card.
When soft or delicate specimens are preserved in a bottle of fluid they
frequently require some kind of support to keep them in proper form and
to display them better for observation. Perhaps the best way to support
them is to fasten them to a very thin plate of mica of suitable size by
means of a needle and very fine thread. The mica is so transparent that
it is invisible in the fluid, and the few stitches are also hardly
perceptible, thus making it appear as if the specimen floats freely in
the fluid.
We will now pass on to consider those objects of the shore that are
usually preserved in a dry condition, commencing with
STARFISHES AND SEA URCHINS
Starfishes are commonly preserved by simply allowing them to dry in an
airy place, with or without direct exposure to the sun’s rays, and this
method is fairly satisfactory when the drying proceeds rapidly; but care
should be taken to maintain the natural roughness of the exterior as
well as to have the numerous suckers of the under surface as prominent
as possible. If the starfish is simply laid out on some surface to dry,
the side on which it rests is often more or less flattened by the weight
of the specimen itself, which therefore becomes adapted for the future
examination of one surface only; but a better result, as regards both
the rapidity of drying and the after appearance of the specimen, may be
obtained by suspending it on a piece of fine net or by threads. A still
better plan is to put the dead starfish into _strong_ spirit, which will
rapidly extract the greater part of the moisture that its body
contained. After allowing it to remain in this for a day or two to
harden it, put it out to dry as before mentioned. The spirit, being very
volatile, will soon evaporate, so that the specimen will shortly be
ready for storing away.
It is most important to observe that dried specimens--not starfishes
only, but all animal and vegetable objects--should never be placed in
the cabinet or other store-case until _perfectly_ dry, for a very small
amount of moisture left in them will often encourage the development of
moulds, not only on themselves, but on other specimens stored with them.
Very small and delicate starfishes, when preserved in a dry condition,
may be protected from injury by fastening them on a card by means of a
little gum, or by keeping them permanently stored on cotton wool in
glass-topped boxes.
Sea urchins, or sea eggs, as they are commonly called, may be preserved
exactly in the same way as starfishes, though it is more essential in
the case of these to soak them in strong spirit previous to drying,
otherwise the soft animal matter within the shell will decompose before
the drying is complete. Here, however, it is possible to remove the
whole interior with the aid of a piece of bent wire, and to thoroughly
clean the inner surface of the shell before drying it.
Some of the shells should be preserved with the spines all intact, and
others with these removed in order to show the arrangement of the
plates which compose the shell, as well as the perforations, and the
rounded processes to which the spines are articulated.
The majority of sea urchins are provided with a most complicated and
beautiful arrangement of teeth which are well worthy of study. These
should be removed from a moderately large specimen, the soft surrounding
structures carefully dissected away, and then cleaned by means of an old
tooth-brush without disarranging them.
It will be found that dried sea urchins will require care when preserved
with spines attached, for these appendages are usually very brittle and
are easily dislocated at their bases where they are united to the shell
by ball-and-socket joints.
It may be mentioned here that corrosive sublimate is very valuable for
preventing the development of mould on the surfaces of starfishes, sea
urchins, and museum specimens generally. It is best supplied in the form
of an alcoholic solution made by dissolving a few grains in about half a
pint of methylated spirit; the advantage of this over an aqueous
solution being the rapidity with which it dries. In most cases it is
simply necessary to apply the solution to the object by means of a soft
brush, but, as regards starfishes and urchins it is far better to
dissolve a few grains of the corrosive sublimate in the spirit in which
the objects are placed previous to drying.
CRUSTACEANS
The preservation of crustaceans by the dry method often requires some
care and demands a certain amount of time; but the process is never
really difficult, and the satisfaction of having produced a good
specimen for a permanent collection well repays one for the trouble
taken and time spent.
Some of our crustaceans are only partially protected by a firm outer
covering, and almost every attempt to preserve these as dry objects
results in such a shrivelling of the soft tissues that the natural
appearance is quite destroyed. This is the case with some of the
barnacles, and the abdominal portion of the bodies of hermit crabs,
which are, therefore, far better preserved in fluid. Dilute spirit is
quite satisfactory for most of these as far as the preservation of the
soft structures is concerned, but it has the disadvantage that it turns
the shells of some crustaceans red, making them appear as if they had
been boiled.
Other crustaceans are so small, or are hardened externally to such a
slight extent, that they also are not adapted for the dry method of
preservation. Speaking generally, such crustaceans as shrimps and
sand-hoppers are best preserved in fluid, while the different species of
crabs and lobsters are more conveniently preserved dry unless it is
desired to study any of their soft structures.
It is quite impossible to remove the soft parts from small crabs and
lobsters previous to drying them, hence the drying should be conducted
as rapidly as possible, so that no decomposition may set in. Where the
process goes on very slowly, as is the case when the air is damp, or
when the specimens are not set out in an airy spot, a decay of the soft
structures soon proceeds, and the products of this decay will generally
saturate the whole specimen, giving rise to most objectionable odours,
and destroying the natural colour of the shell.
If it has been found that the species in question are not reddened by
the action of methylated spirit, they should be allowed to remain in
this fluid, with a few grains of dissolved corrosive sublimate, for at
least a few hours, and then they will dry rapidly without any signs of
putrefaction; and even those species that _are_ reddened by spirit may
be treated to a shorter immersion in this fluid with advantage.
The specimens should always be set out in some natural attitude to dry,
unless it is desired to spread out the various appendages in some manner
that is more convenient for the study of their structure. A sheet of
blotting-paper may be placed on cork or soft wood, the specimens placed
on this, and the appendages kept in the desired positions when necessary
by means of pins placed beside, but not thrust through them. When more
than one specimen of the same species has been collected, one should be
set in such a manner as to exhibit the under side; and, further, in
instances where the male and female of the same crustacean differ in
structure, as is commonly the case, two of each should be preserved, one
displaying the upper, and the other the under surface.
When perfectly dry, all small crustaceans should be mounted on cards
with the aid of a little gum, and the name and other particulars to be
remembered then written on the card.
The question may well be asked: ‘Which is the best gum to use?’ In
answer to this we may say that gum tragacanth is certainly as good as
any. It holds well, and leaves no visible stain on a white card. A small
quantity of the solid gum should be put into a bottle with water in
which a grain or so of corrosive sublimate has been dissolved. It
absorbs much water, becoming a very soft, jelly-like mass. Any excess of
water may be poured off, and the gum is then ready for use.
The larger crabs and
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