•\ i* *> ^ . ^ ^ V'" % 4 % ** f .^'•« <*, **> c" N C « ^C J,,., o .-&- Thk King of Beasts. ANIMAL LIFE IN THE SEA AND ON THE LAND A ZOOLOGY FOR YOUNG PEOPLE By SARAH COOPER %* ILLUSTRATED NEW YORK HARPER & BROTHERS, FRANKLIN SQUARE 1887 Copyright, 1887, by Harper & Brothers. All rights reserved. TO THE ENTHUSIASTIC CLASSES FOR WHICH THE LESSONS WERE PREPARED THIS BOOK 3s &ffectiottatelB Hkbuateb PREFACE. This book is offered to young people with the hope that it may help them in their studies of natural history. The pleasure of every ramble in the country or by the sea- side is increased by an acquaintance with the animals and plants which are found by the way, and consequently these studies bring their own reward. It is far more charming to gain this knowledge from the objects themselves than from merely reading about them in books ; and it is therefore hoped that each subject which is treated in these pages will be studied from speci- mens actually in hand, whenever it is possible to obtain them. The habit of collecting natural objects and curiosities is a helpful one ; and if young students are careful to find out all they can about these objects, the collection will in time represent an unexpected amount of positive knowl- edge. The aim has been to make this little book accurate, and to bring it up to the present condition of science; at the same time scientific terms have been avoided when others could be substituted for them. Classification has not been made prominent, yet the arrangement of Nicholson has been adhered to throuofhout. VI PREFACE. Starting with the sponge, and going systematically through the animal kingdom, a gradual development has been traced from the simple forms of life up to the high- est, and such subjects have been selected for the purpose as are probably of most general interest. Especial attention has been given to the structure of animals, and to the wonderful adaptation of this structure to their various habits and modes of life. S. C. Philadelphia, June, 1887. CONTENTS. PAGE I. Sponges , 1 II. Hydroids 12 III. Jelly-fishes 18 IV. The " Portuguese Man-of-war." 26 V. Sea- anemones 29 VI. Corals 36 VII. Coral Reefs 43 VIII. Ctenophora 49 IX. Star fishes 56 X. Sea-urchins 63 XI. Crenolds, or Stone-lilies 70 XII. Sea-cucumbers 76 XIII. Earth-worms 82 XIV. Crabs 88 XV. Lobsters 95 XVI. Barnacles 99 XVII. Spiders 103 XVIII. Insects 110 XIX. Bees 119 XX. Wasps and Mosquitoes . 128 XXI. Ants 135 XXII. Oysters 143 XXIII. Mussels and Pectens 149 XXIV. Clams and Razor-fishes 154 XXV. Gasteropods 158 XXVI. Limpets and Land-snails 165 XXVII. The Octopus, or Devil-fish 170 XXVIII. The Argonaut 176 XXIX. The Pearly Nautilus 181 XXX. Backboned Animals 185 XXXI. Fishes 192 VI 11 CONTENTS. PAGE XXXII. The Migration of Fishes 205 XXXIII. Frogs and Toads 211 XXXIV. Turtles 217 XXXV. Snakes 223 XXXVI. Lizards 230 XXXVII. Crocodiles 235 XXXVIII. Characteristics of Birds 243 XXXIX. Birds' Eggs and Nests 253 XL. Swimming-birds (Natatores) 260 XLI. Wading-birds {Oraliatores) 271 XLII. Running-birds {Cursores) 277 XLIII. Scratching-birds (Rasores) 284 XLIV. Climbing-birds (Scansores) 295 XLV. Perching-birds (Lisessores) 302 XL VI. Birds of Prey (Raptores) . 320 XLV1I. The Ornithorhynchus . . 327 XLVIII. Kangaroos and Opossums 333 XLIX. Sloths, Armadillos, and Great Ant-eaters. 338 L. Whales 344 LI. Horses 353 LII. Deer 358 LIII. Camels 368 LIV. Elephants 372 LV. Lions and Tigers 377 LVI. Seals and Walruses 382 LVII. Beavers and Squirrels 387 LVIII. Bats 395 LIX. Monkeys 398 LX. Man 406 ILLUSTRATIONS. The King of Beasts Frontispiece. FIG. PAGE 1. Sponge 1 2. Sponges Growing 2 3. Groups of Spicules 3 4. Circulation of Water through the Sponge 4 5. Living Sponge in Action ... 4 6. Neptune's Glove 5 7. Venus's Flower-basket 7 8. Sponge -fishing 9 9. Glass Sponge 10 10. Hydroids growing on a Shell 12 11. Hydroid Magnified, showing Spore-sacs 14 12. Jelly-fish (Aurelia Aurita), with Young in various Stages 16 13. Section of Jelly-fish, showing Tubes and Mouth 18 14. Jelly-fish {Cyancea Enploca- mia) 19 15. Lasso-cells from a Fresh-wa- ter Hydroid (magnified). . 20 16. Mushrooms of the Sea 23 17. Group of Phosphorescent An- imals 24 18. " Portuguese Man-of-war ''. . 28 19. Stomach and Chambers of Sea-anemone 30 20. Cluster of Anemones 32 2-1. Sea-anemones 34 FIG. PAGE 22. Branching Coral Alive, with Polyps expanded 37 23. Astraea Pallida (natural size) 39 24. Mushroom Coral 40 25. Organ-pipe Coral 41 26. Fragment of Red Coral with Polyps 42 27. Formation of Coral Reef. . . 44 28. An Atoll 47 29. Ctenophora 50 30. Cilia on the Gills of a Mus- sel 52 31. Ctenophora and Phosphores- cent Fishes 54 32. Pleurobrachia .... 55 33. Under Side of Ray, showing the Hollow Tubes and the Limestone Plates of the Skeleton 57 34. Star-fishes (lower one show- ing under side and tube- feet) 58 35. Dining upon an Oyster .... 59 36. Interior of Ray 61 37. Under Surface of a Sea-ur- chin, showing Rows of Suckers among the Spines 63 38. Shell of a Sea-urchin without Spines 64 39. Section of a Sea-urchin. ... 65 ILLUSTRATIONS. FIG. PAGE 40. Spine of Sea-urchin (magni- fied) 67 41. Sand-dollar 68 42. Keyhole-urchin 69 43. A Living Crinoid (West In- dies) 71 44. Crinoidal Limestone 73 45. A Fossil Crinoid 74 46. Sea-cucumbers (Holothuri- ans) 77 47. Sea-cucumbers 78 48. A Sea -cucumber (Pentacta Frondosa) 79 49. Sea-orange 80 50. Earth-worm 83 51. Crab 88 52. Early Form of the Crab. . . 91 53. Hermit-crab 92 54. Fiddler-crab 93 55. King-crab 94 56. Lobster {Homarus Vulgaris) 97 57. Acorn-barnacles 99 58. Acorn-barnacle, with Arms extended 100 59. Body of Goose-barnacle. . . 101 60. Goose-barnacles 102 61. Foot of Spider (magnified). 103 62. Geometric Web of Garden- spider 104 63. Spinnerets of Spider 105 64. Female Spider with Young Ones 106 65. Nest of Tarantula 108 66. Diagram of an Insect 110 67. Head of a Bee, showing Compound Eyes, Simple Eye?, and Antennas Ill 68. Alimentary Canal of a Bee- tle 112 69. Tracheae of an Insect, show- ing Elastic Spiral Thread 112 70. Butterfly in the Larva, Pupa, and Imago State. ...... 113 FIG. 71. 72. 73. 74. 75. 76. 11. 78. 79. 80 81. 82. 83. 84. 85. 86. 87. 89a 90. 91. 92. 93. 94. 95. 96. 97. 99, PAGE Scales on the Wing of a Moth 114 Butterflies 115 Moth and Lame 117 Wings of a Bee, showing the Hooks 119 A Bee's Sting 120 Nest of Carpenter-bee. . . . 120 Nest of Humble-bee 121 Hive -bees 122 Little Plunderers 123 Digger-wasp — Cocoon and Larva 128 Nest of Mud-wasp 129 Nests of Social Wasps. . . . 130 Hornets' Nest 131 Different Stages in the Growth of a Mosquito. . 133 Ant Nest, with Under- ground Passages 136 Larva, Cocoon, and Pupa? of Red Ant (magnified). . 137 Slave-making Ant (magni- fied) 138 Queen of Slave - making Ants (magnified) 141 Oyster in the Shell (with mantle removed from the upper surface) 144 Bunch of Mussel-shells.. 149 Pearl-bearing Shells 152 Pecteu Shell 153 Inside of a Clam-shell. . . . 154 Clam (Madra) 156 Razor-shell (Solen) 157 Section of a Spiral Uni- valve 158 Whelk 159 Lingual Ribbons 160 Clam-shell bored by Lin- gual Ribbon of Gaster- opod , . . . .... 161 Sea -shells 162 ILLUSTRATIONS. \1 FIG. PAGE FIG. PAGE 100. Egg-cases of Whelk 163 132. A Fishing Fleet 206 101. Egg-cases of Pear-conch. 163 133. Male Salmon 207 102. Natica 164 134. Salmon-fishing 208 103. Egg-case of Natica 164 135. Female Salmon after 104. Limpet-shell 165 Spawning 209 105 Anatomy of a Snail An Edible Snail Octopus 167 168 170 136. 137. 138. The Frog 1 >11 106 Frogs' Eggs 911 107. From a Tadpole to a Frog 212 108. Suckers on the Arm of a 139. Skeleton of Frog 214 Cuttle-fish 171 172 140. 141. Toads' Eggs Skeleton of the Tortoise 215 109. The Parrot's Beak 110. Cuttle-fish (one -fifth nat- (plastron removed). . . . 218 ural size) The Squid 173 174 142. 143. Box-tortoise 918 111. Circulation in Reptiles. . . 219 112. Egg-cluster of Squid .... 175 144. Green Turtle 221 113. Argonauts 177 145. Hawk's-bill Turtle 222 114. Pearly Nautilus, with Shell 146. Skull of Boa-constrictor. . 224 cut open (one-half nat- 147. Poison Apparatus of the ural size) 182 Rattlesnake 225 115. Ammonite 183 148. Rattlesnake 227 116. A Vertebra 185 149. Cobra de Capello 229 117. Skeleton of a Lion 186 150. Lizard 231 118. Human Brain and Spinal 151. The Chameleon 232 Cord sending off Nerves 187 152. The Iguana 233 119. Arm and Leg of a Man as 153. The Horned Toad 234 thev are Seen when on 154. Crocodile-hunting 236 All fours 188 155. 156. Mouth of the Crocodile. . Alligator 987 120. Hind-leg of Alligator and 238 Fore-leg of Seal 189 157. Just Hatched 239 121. Fore and Hind Leg of a 158. Footprints of Labyrin- Tapir 190 thodon 240 122. Blood Corpuscles of Man . 191 159. "The North Wind." 244 123. Nest of the Sun-fish 193 160. Skeleton of a Vulture. . . 245 124. The Fins of a Fish (pike- 161. Bones of a Wing 246 perch) 195 162. Leg of a Bird perching. . 247 125. Anatomy of the Carp. . . . 197 163. Digestive Organs of a 126. Plan of Circulation in Fowl 248 Fishes 198 164. Plan of Circulation in 197 Flying-fish 199 200 165. Birds and Mammals. . . Parts of a Feather 949 128. Nest of the Stickleback . . 251 129. The Sea-horse 201 166. Section of a Hen's Egg 130. Shark 202 before Incubation 254 131. Egg of a Shark 203 167. Building the Nest 255 xu ILLUSTRATIONS. FIG. PAGE FIG. 168. Nest of the Tailor-bird . . . 257 210. 169. Nest of the Weaver-bird . 258 211 170. Wild Ducks 260 212 m. Foot of a Gannet. 261 213. 172. Flamingoes 263 173. A few Sea-birds 264 214. 174. Sea-gull.'. 265 215 175. Stormy Petrel 265 216. 176. The Albatross 266 177. The Eider-duck 267 217 178. Penguin . . 268 218. 179. Pelicans 269 219 180. Haunt of the Heron 271 181. Crane 272 220. 182. Marabou Stork and Young 273 221. 183. Stork's Nest 274 222 184. The Sacred Ibis 275 185. The Ostrich 278 223 186. Hunting the Ostrich 279 224. 187. Emu and Wolves 281 225. 188. The Apteryx 282 189. Peacock 285 226. 190. Argus Pheasant 286 191. Impeyan Pheasants (India] 287 227. 192. A Partridge 288 193. Partridges in Winter. . . . 289 194. The Quail and her Nest. . 290 228. 195. A Pigeon-loft 291 229 196. Dodo and Apteryx 293 230. 197. Birds of a Feather 294 231. 198. Parrots 295 232 199. Foot of Parrot 296 233 200. Tongue of Woodpecker. . 296 234 201. Woodpeckers at Home. . . 297 202. Woodpecker's Nest 298 235 203. Toucan 299 236 204. Trogon Elegans 300 237 205. Oriole feeding its Mate. . 303 206. Frolic in the Snow 305 238 207. Summer Yellow-birds . . . 306 239. 208. The Crossbill 307 240 209. Two- horned Horn bill feed- 241 ing its Mate 308 242 PAGE Bird-of-paradise 309 Play-house of Bower-bird 310 House-wrens 311 Broad - tailed Humming- birds 313 The Nightingale 315 Nest of Edible Swallow. . 317 Home of the Bank- swal- low 318 Whippoorwills 319 Hawk and Humming-birds 320 Claw and Beak of Bird of Prey 321 The Golden Eagle 321 Eagle's Nest 322 The Fish -hawk and its Nest 324 The Owl 326 Ornithorhynchus 327 Burrow of Ornithorhyn- chus 329 Ornithorhynchus and Por- cupine Ant-eater 330 Heads and Feet of Duck, Ornithorhynchus, and Porcupine Ant-eater. . . 331 The Home of the Kangaroo 334 Kangaroos 335 Virginia Opossum 337 Sloth 338 Armadillo 339 Three-banded Armadillo. 340 Armadillos Rolled for Pro- tection 341 Great Ant-eater 342 Megatherium 343 Whale, with its Young Calf 345 Greenland Whale 347 Whalebone 348 Sperm-whale 349 Dolphins 350 The Narwhal 351 ILLUSTRATIONS. X11L FIG. PAGE 243. Horses 353 244. Group of Horses 355 245. Zebras 357 246. Stag, or Red-deer 359 247. Stomach of a Ruminating Animal 360 248. Reindeer digging in Snow 361 249. Travelling in Lapland . . . 362 250. Antelope 363 251. The Koodoo 364 252. The Gazelle 365 253. The Graceful Chamois. . . 366 254. Camel 368 255. Skeleton of a Camel 369 256. Bactrian Camel 370 257. The Llama 371 258. African Elephants 373 259. Indian Elephants 374 260. Lions 377 261. Foot of a Lion 378 FIG. PACK 262. Tiger attacked by a Croco- dile 380 263. Leopard 381 264. Herd of Seals 382 265. Harp-seal Mother and her Little One 383 266. Walruses 385 267. Beaver 387 268. Skull of a Beaver 389 269. Squirrels 391 270. Flying- squirrels 393 271. Skeleton of a Bat 395 272. Bat 397 273. White -throated Sapajou. 399 274. Mandrill 400 275. Skeletons of Man, Chim- panzee, and Orang. . . . 401 276. Female Orang-outang. . . . 402 277. Chimpanzee 403 278. Gorillas 404 ANIMAL LIFE IX THE SEA AND ON THE LAND. SPONGES. SUB-KINGDOM, PROTOZOA : CLASS, RIIIZOPODA. 1. Sponges. — Sponges are so common and so familiar that many of us have used them all our lives without stopping to admire their curious and interesting structure, or to inquire into the history of their past lives. We may, indeed, have noticed that they can be squeezed into a very small space, and that they will return to their natural shape when the pressure is removed. Perhaps we have also noticed that they are full of little holes or pores, and that they will absorb a large quantity of water. 2. Are Sponges Animals or Vegetables? — You know there has been a doubt whether sponges belong to the animal or to the vegetable kingdom. Fig;. 1. — Sponge. For a Ion of time naturalists ANIMAL LIFE IN THE SEA AND ON THE LAND. were uncertain about the matter, but it is now settled that they are animals, living and growing on the bottom of the ocean. The only part of the sponge that reaches us is the skeleton. The living sponge is a very different object. Shall we see what we can find out about it ? 3. Lowest Forms of Animals. — Upon nam- ing the word " animal," a picture comes be- fore our minds of some creature having a mouth to eat with, and eyes to see with, and possessing feet or wings, or some other means of moving about ; but the sponges are far from this. They are probably the lowest form of animals with which you are acquainted. They have no nerves, no heart, no lungs, no mouth, and no stomach. 4. Live Sponges. — Live sponges consist of jelly - like Fig. 2. — Sponges Growing. SPONGES. ' 3 bodies united in a mass, and supported by a framework of horny fibres, and needle-shaped objects called "spicules," which you will see in Fig. 3, and which we must examine further after a while. This jelly-like flesh, covering all parts of the skele- ton, is about as thick as the white of an egg, and it decays immedi- ately after the death of the sponge. During life the flesh presents many bright colors ; in some species it is r . „ p A „ & ' * Fig. 3. — Groups of Spic- of a brilliant green, while in others ules. it is orange, red, or yellow. 5. Framework. — The framework varies in different kinds of sponges. In those which are valuable for our use this framework consists of horny fibres interwoven in all directions until they form a mass of lacy net-work. This you can easily see with the naked eye, but by looking through a microscope you will see beauty you had not imagined. In our ordinary sponges these fibres are all that remain of the former living animal, the soft flesh with which they were covered having been removed. It is found that the horny fibres are composed of a substance very similar to the silk of a silk-worm's cocoon. They are exceedingly tough and durable. 6. Use of Pores. — In looking at any sponge you will notice large holes through it, with many small pores scat- tered between them. The living sponge draws in water through these small pores, and countless streams are con- tinually flowing through every part of the sponge, bring- ing in little particles of food, and all the air it needs for breathing purposes. 7. Cilia, and the Currents they produce.— In order that we may understand the curious circulation in sponges, let 4 ANIMAL LIFE IN THE SEA AND ON THE LAND. us examine Fig. 4, which shows a small section of a sponge with its branching canals. One large hole is shown at d and the smaller pores at b, while in those cup-shaped hollow Fig. 4. — Circulation of Water through the Sponge. places in the canals marked c we may see a number of fine threads, or " cilia." The word cilia means " eyelashes," but we must not mistake these threads for hairs like our eye- Fig. 5. — Living Sponge in Action. lashes, because they are, in fact, formed of soft, delicate flesh. It is their business to wave gently but continually, and thus urge onward the flowing current of water. Notic- SPONGES. ing the arrows, we may now follow the direction of the tiny streams as they enter the small pores, pass through the canals, and are finally thrown out from the large holes on the surface. With a microscope little fountains like those represented in Fig. 5 may be seen constantly play- ing from the large holes of a living sponge. 8. How Sponges Eat. — Everything that lives must eat and breathe, but how is the sponge to eat without a mouth ? When the food touches any part of its body, the soft, jelly-like flesh sinks in to form a little bag, and at the same time the sur- rounding parts creep out over the morsel of food until it is entirely covered and digested. After this the flesh returns to its original position, and any shell or other refuse that remains from the meal is washed away. 9. The Young. — Sponges have a curious manner of producing their young. At certain seasons very small oval masses of jelly are formed on the inner surface of the canals, which finally drop off. They remain in the canals for a time, and become perfect eggs, after which Fig. 6. — Neptune's Glove. 6 ANIMAL LIFE IN THE SEA AND ON THE LAND. they are thrown out by the water forming the little foun- tains, and instead of falling to the bottom, as we might suppose such helpless masses of jelly would do, they swim around as if they meant to have a little sport before com- mencing the sober realities of life. 1 0. Food for other Animals. — You will be interested to know that while these jelly-like eggs were resting in the canals of the parent sponge, delicate cilia (which we learn- ed about just now) were forming at one end of the egg. These cilia strike the water with a rapid motion, and the eggs are rowed about through it until they settle down and attach themselves to some rock or shell on the bot- tom of the ocean, and finally grow up into the perfect sponge. The waters are swarming with these eggs at certain seasons, and great quantities of them are eaten by larger animals. 11., Size and Shape. — Sponges are common in nearly all parts of the world, and they differ greatly in size and quality, but only a few species are useful to man. Some species are nearly round, others are always cup-shaped, some top -shaped, and some branched. A fresh -water sponge is frequently found in our streams, growing upon sticks and stones. It is of a bright green, and when seen under the water in the sunlight it is very pretty. 1 2. Spicules of Sponges. — The spicules of sponges grow in a variety of elegant shapes; generally they are visible only with a microscope. They are composed of lime or flint, and are usually sharp-pointed. They are embedded in the flesh as well as in the horny fibres, thus serving to protect the helpless creatures from being devoured by fish and other animals. In our fine sponges the skeleton is almost destitute of spicules, while in some others these spicules are very numerous and wholly support the flesh. Fi£. 1. — Venus's Flower-basket. SPONGES. Such sponges are so loose in texture that they are of no val- ue for domestic purposes. 13. Where Found. — Fine sponges are used by physicians in surgical operations, and are sometimes very expensive. Our finest sponges come from the Med- iterranean Sea and the Red Sea. They are obtained by divers, who search for them under rocks and cliffs, and who remove them carefully with a knife, that they may not be injured. The Turks, who carry on the trade, have between four and five thousand men em- ployed in collecting sponges, and the value of those col- lected each year is estimated at ninety thousand dollars. Coarse varieties are found in the Gulf of Mexico and the Bahama Islands. They are scraped off the rocks with forked instruments, and consequently.they are often torn. 14. Method of Culture. — The demand for sponges has 1* 10 ANIMAL LIFE IN THE SEA AND ON THE LAND. increased so much during the last few years that there is cause to fear the supply will be exhausted, unless some way can be found to cultivate them by artificial means. With this view, attempts have recently been made to raise sponges in the Adriatic Sea and in the Gulf of Mexico, by taking cuttings from full-grown ones and fastening them upon stones on the bottom of the ocean until they attach themselves. These experiments have been success- ful, but the operation is a delicate one, requiring great care not to bruise the soft flesh. It is necessary to keep the sponge under sea-water during the process. 15. Glass Sponges. — Some of the glass sponges are exceed ingly beautiful. One of these, the delicate " Venus's flower-bas- ket," grows in the deep sea near the Philippine Islands. It looks like spun- glass woven into a beautiful pattern, and is so ex- quisite we can scarcely believe that it is the skeleton of a sponge. Fig. 9 shows another variety of glass sponge found between Gibraltar and the island of Madeira by the scientific par- ty on board the famous Chal- lenger, which ship was sent out by the British Government to explore the animal and vege- table wonders of the great deep. 16. Boring Sponges. — The "boring sponge" spreads it- self over the shells of oysters and mussels, boring them WmtA Fi£. 9. — Glass Sponge. SPONGES. 11 through and through, and dissolving the shell. It even bores into solid marble, and will, in time, completely de- stroy it. 17. Flints are exceedingly hard substances, yet they are supposed to have been formed from soft sponges. By examining small pieces of flint under a microscope the texture of the sponge, in a fossil condition, is often clearly seen, and the spicules peculiar to sponges are recognized. 12 ANIMAL LIFE IN THE SEA AND ON THE LAND. II. HYDROIDS. SOME ODD RELATIONS OF THE JELLY-FISHES. SUB-KINGDOM, CCELENTERATA : CLASS, HYDROZOA. 1. Hydroids, or Sea-firs. — Let us now examine some odd- looking animals called " hydroids," or sea-firs, which grow in the ocean, firmly rooted upon the bottom, or at- tached to shells and stones. The tall branches in Fig. 10 are hydroids growing upon the shell of a dead mussel. A barnacle, too, has lived and died on this pretty shell, and little sea-weeds cluster around its remains. 2. Related to Jelly-fishes.— We can scarcely imagine an- imals that are more unlike jelly-fishes than these slender branching hydroids are; and yet the wonderful story I have to tell you will show them to be so closely related that we could not study the life of one without studying the life of the other. 3. Their Resemblance to Plants. — Long graceful sprays -Hydroids growing on a Shell. HYDROIDS. 13 of hydroids are often thrown on shore by the tide, and as they resemble plants much more than animals, they are generally mistaken for sea- weeds. Many persons gather them for decorating brackets and hanging-baskets, and we frequently see bunches of them arranged in sea-shells, and offered for sale in our shops. The shopkeeper would prob- ably not know them by any other name than sea-weed. Still, they are animals, and we can mostly recognize them by their yellow, horny appearance, and by the numerous joints on their stems. 4. Each Spray-point bears a Cup. — In looking at one of these sprays with a microscope you will find each little point on the stem to be in reality a dainty cup, which when alive contained a hungry animal. Should you find a piece freshly washed up from the ocean, it would be well to place it in a glass jar filled with sea-water, and after allowing it to remain perfectly still for a while, it may perhaps show you, if it is yet alive, how it has been accustomed to pass the quiet hours in its native home. 5. Hydroids higher in the Scale of Life than Sponges. — You will find each cup occupied by a soft animal, with a mouth in the centre opening directly into the stomach. Hydroids, you see, are higher in the scale of life than sponges, for they possess mouths and stomachs. As we watch, the body of the animal will rise up in the cup, and from around the mouth will gradually creep out slender thread-like feelers, which may be extended quite a dis- tance, or drawn up at will entirely within the body of the animal. You will, of course, wish to use the proper name for these feelers. They are called tentacles, and they evi- dently serve to produce currents of water towards the mouth, and to bring the required food. In this way the little animals live, day after day and year after year, pa- 14 ANIMAL LIFE IN THE SEA AND ON THE LAND. tiently waving their tentacles, and waiting for the food that is sure to come. 6. How Hydroids produce Jelly-fishes.— Do you ask what connection there is between these quiet little animals and the active jelly-fishes ? We shall soon see. The hydroids have grown by budding and branching somewhat as plants do. Occasionally pear-shaped cups much larger than those we have looked at are formed on the stem. These large cups are called spore - sacs. They contain the substances which, later, will grow into eggs, and at the proper time they fall off. After resting a while, and throwing out cilia and tentacles, these spore-sacs swim gayly away, and, strange to relate, they are henceforth known by the name of jelly-fishes! 7. The Spore-sacs. — In Fig. 11 you will see a spray of hydroid magni- fied which shows two spore-sacs. In the species which is represented here (the Sertularia) the spore- sacs do not fall off, but they burst and discharge the eggs which they contain. These jelly-fishes now lead active lives, and as they dart and swim about in the water no one would suspect that they had any relation to the plant-like animals w T ith which we started, yet it is supposed that most hydroids have this wonderful history. 8. The Young unlike their Parents. — Jelly-fishes produce eggs, from wdiich are born little floating bodies. These after a time fasten themselves to some stick or stone, and grow by budding until they become the elegant feathery Fig. 11. — Hydroid Mag- nified, showing Spoue- SACS. HYDROIDS. 15 branches which we must now call hydroids. The young of nearly all animals resemble their parents, but the chil- dren of jelly-fishes, you see, are very different from the jelly-fish itself. In the next generation, however, we shall find jelly-fishes again. 9. Difference between Plants and low Forms of Animal Life. — Most of the plant-like objects which we are accus- tomed to see growing near the shore are in reality hy- droids. Has it ever puzzled you to know the difference between plants and these low forms of animal life ? One very important difference is that most plants can procure their food directly from the soil, whereas animals are obliged to feed upon living substances, or those which have at some time been alive, as vegetables and animals. 10. Found in all Parts of the Ocean growing in Families. — Hydroids grow in all parts of the ocean, in deep water as well as near the coast. Some of them are three feet high. One branch may contain a hundred thousand dis- tinct animals, the only communication between them being a circulation of fluid through the hollow stems. In this way each branch constitutes a family which has sprung originally from the same little egg. Some varieties never grow tall, and as they occur in patches over rocks and shells, they resemble thick beds of moss. 11. Another Manner of producing Jelly-fishes. — The lit- tle hydroids which we see hanging from the under side of a rock in Fig. 12 produce jelly-fishes in a different man- ner from the one I have described, although it is equally remarkable. This hydroid has no buds or branches, but the main tube of the body divides itself into a number of rings or plates, until the whole animal looks somewhat like a pile of tiny saucers with scalloped edges. Finally the upper plate begins to twist and squirm until it loosens 16 ANIMAL LIFE IN THE SEA AND ON THE LAND. itself from the pile, and floats off to lead the gay and in- dependent life of a jelly-fish. It is followed by the other plates in their turn, each making a separate animal. These new jelly-fishes eat greedily and grow fast, forming some of our largest varieties. Fig. 12.— Jelly-fish (Aurelia Aurita), with Young in Various Stages. 12. We can form but little idea of the immense num- bers of animals living in the ocean and drawing from the surrounding water all that is needed for their support. They cannot go in search of food, and they take only such as floats towards them. Still, they seem to have some choice in the matter, as they reject from their mouths any food they are not suited with. Many of these curious animals have bright colors, and surrounded as they are with a great variety of plants, they give to the bottom of the ocean a marvellous beauty. HYDROIDS. J 7 13. Does it not seem strange that the slender, delicate sprays of which we have been speaking are really animals, and more than that, the children of jelly-fishes ? A little girl once exclaimed, on hearing of these wonderful changes that happen in the life of hydroids, " Why, it seems almost like a fairy-tale !" 18 ANIMAL LIFE IN THE SEA AND ON THE LAND. Ill JELLY-FISHES. SUB-KINGDOM, CCELENTERATA: CLASS, HYDROZOA. 1.* Jelly-fishes, — When jelly-fishes are seen lying in shapeless masses upon the beach, where they have been washed by the tide, their appearance is not attractive. If, however, we can watch them from the side of a boat, or from a long pier, as they dart through the water with their ten- tacles trailing after them, we shall soon learn to admire their graceful movements and their elegant colors. There is something very interesting too in these little inhabitants of the great deep. They are such soft, helpless things, yet they live and have their own good times if only the boisterous waves do not catch them and dash them too harshly against the rough shore. 2. Jelly-fishes a single Bell-shaped Mass. — Jelly-fishes consist of a sin- gle bell-shaped mass of jelly, from the inner surface of which hangs the body of the animal, with the mouth in the centre. The mouth opens directly into the stomach, from which several hollow tubes (usually four) extend to a circular tube around the edge of the bell. In the jelly- Fig. 13. — Section of Jel- ly-fish, SHOWING TOBES and Mouth. JELLY-FISIIES. 19 fish (Fig. 13, a), the side next to us has been removed, that we may see the tubes and the mouth hanging in the centre; b shows us the same viewed from below. 3. Eggs of Jelly-fishes. — The eggs of jelly-fishes are formed in large quantities in the tubes leading from the centre. Fig. 13 shows the en- larged cavities con- taining eggs. At certain seasons of the year great clus- ters of bright -col- ored eggs may be seen through the transparent flesh. A few jelly-fishes are thought to pro- duce young ones resembling them- selves,without pass- ing through the strange forms we noticed in studying hydroids. 4. How they Move. — Hydroids, you will remember, are abundant in all oceans; so are jelly-fishes, and they are often found floating in large companies. Jelly-fishes are propelled by alternately taking in and throwing out water under the bell. This gives them a jerking movement, as though caused by breathing. They come to the surface chiefly when the water is quiet, and, as they like the 14. — Jelly-fish (Cyangea Enplocamia) 20 ANIMAL LIFE IN THE SEA AND ON THE LAND. warm sun, you will not see many of them at an early hour in the day. They are easily alarmed. If they meet with an obstacle in their course, or if they are touched by an enemy, the bell contracts, the tentacles are instantly drawn up, and the creature sinks in the water. 5. Beginnings of Eyes and Ears. — Upon the outer edge of the bell there are bright-colored specks and solid spots, which are thought to be the beginnings of eyes and ears. Although these spots never grow to be perfect eyes and ears in the jelly-fish, they promise that Nature has in store for her children the precious gifts of sight and hearing. Such imperfect organs are called by the wise men rudimentary or- gans. This is the lowest animal in which anything corresponding to our nerves is found. 6. Power of Contracting and Ex- panding their Tentacles. — Delicate fringes and tentacles hang from the lower edge of the bell, add- ing greatly to its beauty. The tentacles are often many feet long, yet the animal has the pow- er of drawing them up so that they are not visible. This curi- ous power of contracting and expanding the tentacles belongs to many humble sea creatures. Sometimes, while we are wonder- ing at their disappearance, they lengthen again as if by magic. 7. How Jelly-fishes secure Food.— The tentacles of jelly- fishes arc covered with a great many lasso-cells. These Fig. 15. — Lasso-cells from a Fresh -water Hydroid (Magnified). a, Barbed Dart within the cell ; b, Barbed Dart escaped from the cell; c, Lasso fully ex- tended, carrying the dart at the end. JELLY- FISH ES. 21 lasso -cells are too small to be seen without a micro- scope ; still, they are powerful weapons in their way, and are quite sufficient to enable the jelly - fish to catch its food. You know how the skilful hunter uses a lasso for catching wild cattle. The jelly-fish uses its lasso in quite a different manner, but it may be equally effective. 8. Lasso-cell. — When examined, each lasso-cell, or little sac, is found to contain a long slender thread coiled within it, somewhat like a lasso, and floating in a fluid. The cell is filled so full of the fluid that it bursts with the slightest touch, and as the fluid squirts out, it carries with it the slender lasso armed with sharp stings. In this way lassos are darted out to capture many little crabs or fishes that brush too near in passing. 9. Description and Use of Lasso. — The sting of the lasso seems to paralyze the unfortunate creatures, and they make no effort to escape as the tentacles coil round them and carry them to the mouth of the greedy jelly-fish. In Fig. 15 you will see a group of lasso -cells highly mag- nified. The cell at a has not yet burst, and through its thin walls we see the barbed dart at the end of the lasso. At b the lasso has been thrown out only a short distance, while at c the long slender lasso still carries the dart at the end, and the curious little bladder is much larger than it was inside the cell. The lasso of this specimen is exceed- ingly delicate and simple, while that of some animals is covered with stinging bristles. Is it not a dainty weapon to be used in the continual warfare carried on by these innocent-looking creatures? Small as the lassos are, they serve to protect the soft- bodied animals from their nu- merous enemies. 10. Sea-nettles— Medusae. — If we should touch the soft, 22 ANIMAL LIFE IN THE SEA AND ON THE LAND. pretty tentacles of a jelly-fish, we should probably be stung by these tiny weapons. This irritation is produced in the flesh by the numerous sharp points on the lassos, and is similar to the stinging of nettles. For this reason jelly- fishes are often called sea -nettles. The correct name, however, which you will find in scientific books, is "Me- dusae." 11. Size. — Jelly-fishes vary greatly in size. Some are mere dots, so extremely small that we might not notice them in the water, while one species is said to be seven feet in diameter, with tentacles measuring fifty feet in length. The parent of this huge jelly-fish was a hydroid only half an inch high. Its children will be the same. What do you think its grandchildren will be ? 12. Nature of the Jelly-like Flesh.— The jelly-like flesh of these animals consists largely of water, and a specimen weighing several pounds when alive will shrink away to almost nothing if exposed to the sun and the wind. As the body contains no bones or other solid matter, it all perishes together, and no trace is left of its former beau- tiful shape. You wall see that jelly-fishes are in no way like real fishes. As they float on the ocean they look more like fantastic mushrooms, and one writer has called them " Mushrooms of the Sea." 13. Color. — It would be impossible to describe the va- ried colors of jelly - fishes, as they include almost every hue, the beautiful tints being probably heightened by their transparency. All shades are to be found, from pale blue and pink to bright red and yellow. Those found in tropical seas are of a deeper color than ours. 14. One Delicate Kind. — In striking contrast with these brilliant jelly-fishes is one species which is so delicate and transparent that as it floats upon the water we can scarce- JELLY-FISHES. 23 ]y see the sub stance of which it is composed. The only parts that strike the eye are the circular tube around the edge and the four ra- diating tubes with their large clusters of eggs. The tubes look as if they were held together by some slight web. This jelly - fish is extremely languid in its 16. -Mushrooms of the Sea. 24 ANIMAL LIFE IN THE SEA AND ON THE LAND. movements, and it sometimes remains perfectly quiet in the bright sunshine for hours, not even moving its tentacles. 15. Phosphorescence. — Although jelly-fishes are so brill- iant in the daytime, they have a different beauty at night, when they throw out a golden light slightly tinged with green, resembling that of a glowworm. Vast numbers of small animals in the sea have this power of giving light from their bodies. The light is called phosphores- Fijjr. 17. — Group of Phosphorescent Animals. cence. As it may be seen at any time of the year illu- minating all oceans, it is an unfailing source of delight to voyagers. It is most conspicuous on a dark night, when the water is agitated by the motion of a boat, or by JELLY-FISHES. 25 the breaking waves. In Fig. 11 is a group of the larger phosphorescent animals. 16. A pail of sea-water carried into a dark room often affords a good opportunity for studying this interesting phenomenon. Although we may not have detected the presence of any animals before, when the water is stirred or jostled we may see the beautiful sparkles of light. The phosphorescence of some animals is of a bluish tint; in others it is red, like flame. 17. A person will rarely tire of watching a boat as its prow turns up a furrow of liquid fire, and each dip of the oar sends a miniature flash of lightning through the otherwise dark water. . 26 ANIMAL LIFE IN THE SEA AND ON THE LAND. IV. THE "PORTUGUESE MAN-OF-WAR." SUB-KINGDOM, CCELENTERATA : CLASS, HYDROZOA. 1. Some one bas probably imagined that this curious floating animal looks like a Portuguese war vessel, and on that account has given to the innocent and defenceless creature a name which seems to us very inappropriate. We will not be dismayed, however, by a forbidding name, for the graceful animal is not in the least warlike. It is to be hoped you may all have the pleasure some day of seeing one floating over the sea like a fairy vessel, not minding the winds or the storms. You will be delighted with its beauty, and you will wonder how so frail a bark can withstand the waves. 2. Shape and Color. — When we examine the Portuguese Man-of-war we shall find it to be a transparent pear- shaped bladder, about nine inches long, throwing off, like a soap-bubble, bright blue colors tinged with green, vio- let, and crimson. On top of the bladder there is a wavy, crumpled crest of delicate pink. This may perhaps act as a sail. 3. A Colony of Animals. — From one end of the bottom hangs a large bunch of curious - looking, bright - colored threads, and bags, and coiled tentacles which trail after it. You will see these streamers in the picture, and you may be surprised to learn that they are separate animals, forming a little colony, which is floated by the bladder. THE "PORTUGUESE MAN-OF-WAR." 27 Still, they are not entirely distinct; they have various uses, and each contributes its share to the good of the colony. Some produce eggs, some do the swimming, some do the eating, and others are provided with lasso-cells to procure food. 4. The Food taken by One nourishes All. — In such col- onies of animals as this, the food which is taken by one individual helps to nourish all the others. This is accom- plished by the circulation of fluids throughout the whole colony, carrying nourishment to each one. 5. Organs Defined. — In animals that are more highly de- veloped we shall find these offices performed by special parts of the same body. These different portions of the body, which are set apart to perform certain duties, are called organs. Thus we speak of the eye as the organ of sight, and the ear as the organ of hearing. 6. Length of Tentacles. — The tentacles of the Portu- guese Man-of-war are more than twenty feet long, yet they may be drawn up to within an inch of the bladder. The lasso -cells upon their surface not only wound the prey, but also sting bathers or any persons who come in contact with them. Even after death the tentacles pro- duce irritation when they are touched. 7. Where Found. — These beautiful creatures are found in tropical seas. They are abundant in the Gulf of Mex- ico, and are often carried by the Gulf Stream into North- ern waters. Occasionally they drift upon our own shore. Do you think you would recognize one floating on the ocean when you had not expected to see it ? If you should ever have one in your possession, it may be well to dry it or keep it in alcohol ; for although its delicate beauty cannot be preserved, it will still be interesting to those who have never seen living ones. 28 ANIMAL LIFE IN THE SEA AND ON THE LAND. 8. In watch- ing the " Por- tuguese Man- of-war" you will find, at times, that some of its tentacles are drawn up so as scarcely to be seen ; but sud- denly these are let down, and others dis- appear. Soon they may all be extended to their full length, then strangely curled and twisted. 9. Floating in Companies.— One might sup- pose these animals were fond of society, since they are sometimes seen floating in large com- panies, which have been fancifully called fleets. Travellers occasionally speak of meeting great numbers of them, both large and small, stud- ding the surface of the ocean: probably the young ones were out sailing with their parents. 18.- PORTCGUESE MaN-OF-WAR.' SEA-ANEMONES. 29 V. SEA-ANEMONES. SUB-KINGDOM, CGELENTERATA : CLASS, ACTINOZOA. 1. Ocean Treasures. — Many of you, no doubt, have learned, when at the sea - shore, the delight of climbing over wet rocks covered with slippery sea-weed, and peer- ing into the little pools left between the stones to see if the great waves have dropped any treasures from the ocean. Those who have enjoyed this pleasure will gladly recall the sparkling pools, carpeted with rich-colored sea- weeds which half conceal the timid animals that live there. 2. In such pools the rocks, the shells, and the sea-weeds all have richer tints from the bright water that covers them, and one who loves beautiful things will linger be- side the pools as if gazing into enchanted gardens. 3. Sea-anemone. — On searching these rock pools we shall probably find many curious animals. None would interest us more than the "sea-anemone," though when we find it hiding in some dark corner, with its tentacles all drawn in, and looking like a soft lump, it may not promise much beauty. 4. Why so Named. — The sea-anemone adheres firmly to the rocks, so we will not pull it off. If we watch long enough we shall see it begin to rise in the middle, and from the summit will creep out, very slowly and softly, 30 ANIMAL LIFE IN THE SEA AND ON THE LAND. beautiful tentacles like a wreath around the top. It is now that this singular animal looks like a flower, and de- serves the name that it possesses. Perhaps it is not so much like an anemone as it is like a chrysanthemum or some other flower with a great many petals. You will be charmed with the delicate light-colored tentacles waving gently in the water. 5. Description. — In the middle of the tentacles is the mouth, leading into a hollow sac, which is the stomach. The remainder of the body is divided by partitions from top to bottom into open chambers. In Fig. 19 you will see the stomach at e, and the chambers at k. There is an opening at the bot- tom of the stomach through which the food passes after it is digested. Sea-water also en- ters the body through the stom- ach, and both the water and the nourishment circulate freely through the chambers. Each tentacle is a hollow tube connected at its- base with one of the chambers, and readily filled with water. Here we have an explanation of the mysterious manner in which the sea-anemone swells itself out and then shrinks away again. The body and tentacles are Fh 19. — Stomach and Chambers of Sea- anemone. c, tentacles; d, month; e, stomach; g', g\ openings in the partitions ; k, chambers. SEA-ANEMONES. 31 enlarged, by drawing in water to fill them, and when they suddenly contract the water is forced out through the mouth. 6. No hard Skeleton. — The sea -anemone has no hard skeleton whatever; all parts of the body are soft, like a stiff jelly. It can draw in its tentacles out of sight, and it will do so upon the slightest alarm, rolling itself into an ugly lump like the one we found. Allow it to remain quiet for a while, however, and it will blossom out as gor- geously as ever. 7. The Manner of Feeding. — When any little crab, or worm, or small fish brushes past the tentacles, the lasso- cells are darted out to paralyze it, and the tentacles then seize the prey and carry it to the mouth. The bones or shells which remain after the meal are thrown out from the mouth. The tentacles hold the prey tightly, so that even cunning crabs cannot escape, and you know it is not the easiest thing in the world to catch a crab and hold it. 8. Sea-anemones are greedy creatures. It takes a great deal of food to satisfy their appetites, and their mouths can be extended to receive quite large animals. They eat mussels and cockles by sucking the body out of its shell. Great numbers of sea-anemones, in their turn, are devour- ed by other animals, their soft bodies offering little resist- ance to their foes. 9. Variety of Color. — The variety of color in these ani- mals is almost endless. Some of them are rich orange and chocolate colors, others purple dotted with green. One beautiful species has violet tentacles pointed with white; another, red tentacles speckled with gray. Another spreads out its green arms edged with a circle of dead white, while still another opens a milk-white top circled with a border of pink. In Fig. 20 is a cluster of beauti- 32 ANIMAL LIFE IN THE SEA AND ON THE LAND. ful anemones. The two small ones at the right show how these creatures look when closed. 10. Animals protected by "Mimicry." — Some sea-anem- ones which live in exposed situations are of a dull, dusky brown, covered with rough warts, while animals of the 20. — Cluster of Anemones. same species, living in deep water, where there is less need of concealment, have smooth skins adorned with brilliant tints of rose, scarlet, or light green. This beau- tiful provision of Nature for protecting animals by mak- ing them inconspicuous is called " mimicry." In follow- SEA-ANEMONES. 33 ing oar studies in Natural History we shall find many in- stances of this general resemblance in the color or shape of animals to the objects by which they are surrounded, and we shall notice that the animals are in this way con- cealed from their enemies. 11. Great Numbers of Eggs. — The number of eggs pro- duced by sea-anemones seems almost incredible. A sin- gle animal is said to throw out three hundred eggs in one day. The eggs are little jelly-like lumps which are formed on the inside of the partitions, and are thrown out from the mouth. After swimming about by means of cilia, they settle on some solid body and begin to grow. Sometimes the young ones remain within the body of the parent until their tentacles are formed. They are then ready to settle down soon after reaching the water. 12. Budding and Renewal of Lost Parts. — Sea-anemones increase by budding as well as by eggs. At the lower edge of the body little round knobs are sometimes formed, which separate from the parent and grow into perfect ani- mals. If the tentacles or other parts of the body are re- moved, new tentacles soon grow in their places. If an individual is torn in pieces, each fragment has the power of forming for itself a mouth and throwing out tentacles, and becoming a new sea-anemone, perfect in all its parts. 13. Where Anemones are Found. — Most species live in holes among the rocks, attached to stones or shells, over which they slide in a clumsy way. They are especially fond of deep dark grottos, and when they have taken full possession of such places, they may be found clinging to the sides and roof of the cave, and displaying their charms without reserve. Although they do not enjoy the glare of the bright sun, they expand best in mild, clear weather, and remain closed when the sea is rough and stormy. 2* 34 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fig. 21. — Sea- anemones. 14. A few of these animals float on the ocean. One sea-anemone is fond of a roving life, and having no very good means of travelling about, it attaches itself to the back of a certain kind of crab, and accompanies the crab SEA-ANEMONES. 35 in all its wanderings. There seems to be an attraction between the two, and one is rarely seen without the other. 15. Another species is mostly found clinging to the shell of a whelk, but for certain good reasons it never clings to a living one. The whelk burrows in the sand. This would be disagreeable and inconvenient to the anemone, so it prefers a dead shell which has been taken possession of by a hermit-crab, and henceforth it travels about with the crab. We should scarcely look for affection in a crab, but it has been said that the hermit grows fond of its com- panion, and that when it has outgrown its shell and has selected a new one, it will carefully lift the anemone from the old home and place it on the new one, " giving it sev- eral little taps with its big claws to settle it." 16. A Simple Aquarium. — Do not fail to hunt up these lovely rock pools when you have an opportunity. The pleasure of a visit to the sea-shore is greatly increased by an interest in the strange forms of animal life which we see there and nowhere else. A glass jar filled with sea- water is often a source of great delight. In it you may drop any strange - looking object that has excited your curiosity. Perhaps this very object may prove to be some odd little animal which is not yet dead, but which will revive with the touch of the life-giving water. 17. In this way we may watch their habits and their hidden beauties. Sea-anemones do well in such an aqua- rium, and as they cling to the side of the jar, we can ob- serve all their parts while they are in action. By far the pleasantest way to learn about them is to let them tell their own story. The water must be changed frequently, for impurities are constantly passing from the bodies of even these delicate animals. They will soon die if placed in fresh water. 36 ANIMAL LIFE IN THE SEA AND ON THE LAND. VI. CORALS. SUB-KINGDOM, CCELENTERATA : CLASS, ACTINOZOA. 1. Corals. — Most persons admire corals. They are so common and easily obtained that I hope each of you will lay aside your reading just here, and hunt up a piece, no matter how small, that we may examine it carefully, and see what we can find out about it. You must find, how- ever, a piece of the natural coral, just as it was brought up out of the sea, and not a polished piece such as is made into ear-rings and brooches and strings of beads for ornaments. 2. The Roughness on the Surface. — What makes this bit of natural coral so rough ? The first glance will convince you that those curious pits and little cups on the surface mean something ; and when we remember that all the corals which reach us are the skeletons of former living animals, they interest us at once. 3. Home of the Corals. — Few of us, perhaps, will ever be so fortunate as to see living corals, since they grow prin- cipally in the deep water of warm oceans. The higher the temperature, the greater the variety and profusion of corals. They are delicate creatures, however, as they will not flourish under adverse circumstances. They require water of a certain depth, and they die immediately if exposed to the sun or to cold weather. During life the skeleton is covered with soft flesh, the surface of which is thickly studded with star-like animals called polyps. In CORALS. 37 22. — Branching Coral Alive, with Polyps Expanded. this way millions of polyps are sometimes clustered to- gether in one community. As they wave their delicate tentacles of white, green, or rose color, they are very beau- tiful, especially if seen in bright sunlight through water that is clear and still. 4. A Piece of Coral Examined. — In Fig. 22 is shown a piece of living coral with the polyps expanded. The flesh has been removed from the upper branch on the left that we may see the skeleton. Let us suppose that the speci- mens we have selected for study are of this kind. Each of the tiny cups on the surface was once the framework 38 ANIMAL LIFE IN THE SEA AND ON THE LAND. of a separate polyp, and we shall find that its interior is divided by a number of partitions which do not quite reach the centre. Look into the cups with your micro- scopes,* and you will find them very beautiful. One set of partition-walls reaches almost to the centre, and be- tween these walls are shorter ones. These give us a clew to the kind of animal that has lived here, and they will at once remind you of the partitions in the sea-anemone, as shown in Fig. 19 of the last chapter. Indeed, the whole structure of a coral polyp is similar to that of an anemone, and we can now easily imagine the stomach of the polyp hanging down in the opening left between those delicate partitions. Coral polyps differ from sea-anemones, how- ever, in three important ways — they have hard skeletons, they cannot move about, and they usually grow in clusters. 5. Life History of the Polyps. — When young, coral polyps are little jelly-like animals which swim about in the wa- ter. After they have chosen a resting-place, and the stomach and tentacles have grown, hard particles of lime, which they have drawn in from the sea- water, settle in their flesh to form a circular cup as well as the partitions inside. In this way the polyps soon acquire a solid frame, the soft parts being the stomach, the fringe of tentacles, and the fleshy mass covering the skeleton. They can draw the tentacles entirely within the body, as the anemone does. Like the anemone they also have lasso-cells for capturing their food. 6. How Corals become Branched. — Should it be a branch- ing coral whose history we are tracing, it will now begin * A Coddington lens, which is inexpensive, is a useful thing to possess. It can be carried in the pocket ; and if we have it always with us, we may find new beauties wherever we go. CORALS. 39 to bud from the sides. The buds will grow into branches, throwing out other buds, somewhat as plants do, until Ave have an elegantly branching colony. Each bud is a new polyp, and remains attached to the branch from which it sprang. Although the polyps in such a community have separate mouths and stomachs, there is a close con- nection between them, and a free circulation of fluids through the soft flesh. Fig. 23. — Astr£a Pallida (Natural sizk). V. One Generation after Another. — As in other families one generation passes away and another takes its place, so in large branches of coral the lower and older portions may be dead, and living polyps will be found only at the ends of the branches. 8. The Eggs. — Besides increasing by budding, corals increase rapidly by eggs. Their eggs are pear-shaped, transparent bodies, covered with cilia, which are in con- stant motion, and which row the jelly-like lumps through the water. The parents, you remember, are firmly rooted to some object, but their little ones are gifted for a time 40 ANIMAL LIFE IN THE SEA AND ON THE LAND. with the power of motion. They may well enjoy the privilege while it lasts, for it is their only chance of ex- ploring their ocean home. Presently they must settle down like other sedate corals. It is in this manner that the young polyps are distributed through the ocean instead of growing in a crowded colony around the parent. 9. Coral not Built by an Insect — "Radiates." — You will often hear coral spoken of as having been built by an in- sect, and you will see at once that this is far from correct. Coral polyps are veiy different from insects, and their skeletons grow, much as ours do, inside of the animal; so we cannot say they have been built. All such animals as coral polyps, which have the mouth in the centre, with other parts radiating from it, are called " Radiates." 10. Different Forms of Coral. — Besides these branching Fig. 24.— Mushroom Coral. corals which resemble trees and shrubs, there are other kinds which grow in solid masses without sending off branches. Some assume the shape of graceful vases, and all of these varieties are gayly decked with star-like polyps CORALS. 41 of varied colors. Does it not seem to you as if the ocean was one vast storehouse of beautiful things ? 11. The Mushroom Coral. — The mushroom coral (Fig. 24) looks indeed like a large mushroom, although you will notice that the leaflets are on the upper surface instead of being underneath, as they are in the vegetable mushroom. This coral is the skeleton of one huge polyp, and we see the depression in the centre corre- sponding to the little cups on most other corals. 12. Organ -pipe Coral. — The organ-pipe coral consists of love- ly crimson tubes standing up- right, and connected at short distances by thin flat plates, which give it the appearance of being several stories in height. These plates may be distinctly seen in Fig. 25. When alive, a bright purple polyp protrudes from the top of each tube. 13. Red Coral. — Red coral, which is used for jewellery, grows in a bushy form on rocks at the bottom of the Mediterranean and Red seas. The fleshy mass of this coral is colored red by the numerous red spicules it con- tains, while the polyps themselves are pure white, the whole resembling a pretty red shrub spotted over with sparkling white flowers. The spicules in the centre of the branches form a solid stem, which takes a fine polish. Underneath the flesh the surface of the coral is marked with deep grooves, which are canals for the circulation of water. These grooves are shown at both ends of the 25. — Organ-pipe Coral. 42 ANIMAL LIFE IN THE SEA AND ON THE LAND. brancli in Fig. 26. They are always removed in polish- ing. 14. Red coral is generally obtained by fishermen, who drop into the water heavy wooden crosses to which strong nets are attached. As the boat moves slowly forward, the crosses are raised and lowered to break off the coral branches. The apparatus is then lifted from the water, and the fragments of coral which have become entangled Fier. 26. — Fragment op Red Coral with Polyps. in the net are carefully removed. There are many shops in Italy where the coral is polished and cut into various ornaments. Delicate rose -colored corals are considered very choice and elegant, but the natives of India prefer blood-red ones, which contrast finely with their dark rich complexions. Corals are their favorite ornaments, and large quantities are imported every year. CORAL REEFS, 43 VII. CORAL REEFS. 1. Circular Islands. — The attention of seamen and navi- gators has long been attracted by the number of circular islands in the warm parts of the Pacific and Indian oceans. Generally each one of these circular islands contains a lake of quiet Avater extending almost to its outer shores, so that the island looks like a fairy ring of land floating in the ocean, and adorned with tropical trees and plants. 2. What are Coral Reefs? — Happily for the boys and girls of the present day, this subject, with other equally fascinating branches of science, has now been studied by naturalists, who give us the rich results of their labors. It seems scarcely possible that the dainty, beautiful corals which we have just examined can have anything to do with the making of islands, but nevertheless we find this to be the fact. Coral reefs are vast masses of coral which have grown in tropical oceans, where there is a strong current in the warm water. Their formation must have been slow, yet they sometimes extend hundreds of miles. Many parts of our solid continents are now thought to have been formed from coral reefs. 3. The Beginning of a Reef. — Let us now try to picture to ourselves the beginning of one of these reefs, and by following its growth step by step we may at last under- stand how it has been formed. There are hills and val- 44 ANIMAL LIFE IN THE SEA AND ON THE LAND. leys on the bottom of the ocean as well as on the land. We will fancy that some young coral polyps which have been swimming about in the sea settle on the sides of one of these hills, and begin to grow and spread all around the hill. They will increase also by the deposit of eggs until they form a circular wall. 4. As the coral wall grows, the lower polyps and the inner ones die, their skeletons forming a solid foundation for all that grow above them. There may be only about an inch of living coral on the outside of the reef. a, a, Surface of the Water; b, Natnral Bed of the Ocean ; c, e, Coral Formation : d, Lagoon. 5. How the Lagoon is Formed. — These walls rise nearly straight, and you will see that in doing so they enclose a circular basin of quiet water, and now you can under- stand why it is that a coral island mostly has a lake in the centre, as is shown in Fig. 27. The lakes are called lagoons. 6. Different Varieties of Coral found at Different Depths. — The bottom of the wall is formed of brain-coral and other solid kinds which live only in deep water, and these die when a certain height is reached. The formation of CORAL REEFS. 45 the new island does not stop with their death, however. The wall having now reached the proper height to suit branching corals, which require shallower water, their young polyps will settle upon it, and finish the structure. We might suppose a reef formed of branching corals would be open and unsubstantial, but in their growth the branches are thickly interlaced. The spaces between them become filled with substances floating in the ocean, and with pieces of coral which are broken from the reef by the fierce dashing of the waves. These fragments of coral suffer no serious injury by breaking, but if lodged in some favorable spot they continue to grow, and to- gether they form a solid mass, stronger, perhaps, than any stone masonry. V. The Sea not too Rough for the Polyps. — The outer edge of the wall is steep and abrupt. Soundings taken just outside show very deep water. In this portion of the wall the corals live and thrive, always supplied with clear water, and an abundance of food brought by the rapid current. The breakers dash against it with such fury that apparently the hardest rock must in time yield to the tremendous force of the waves. But, strange as it may appear, the soft jelly-like bodies of the polyps give to the reef the power of resisting the billows. 8. The Inner Surface of the Wall. — The inner surface of the wall slopes gently to the land, and being washed by quiet waters often containing sand and mud, it is not favorable to the growth of polyps. Still, there are certain kinds of coral which thrive within the lagoons, and some of these are exceedingly brilliant and beautiful. 9. How the Island is Raised above the Sea. — The coral polyps die before they reach the surface of the ocean, as no corals can live out of water. The remainder of the 46 ANIMAL LIFE IN THE SEA AND ON THE LAND. island is built up by shells, pieces of broken coral, sea- weed, and other floating materials which are washed upon it, and raise the wall higher and higher. The never- ceasing action of the waves grinds up these shells and broken coral, until at last they form a soil of sand and mud which is now ready to receive any seeds that may float on the water or be brought by the winds and the birds. The seeds take root in the new soil, and young plants begin to appear on the glistening white surface. 10. The Vegetation. — Cocoa-nut-trees are often the first to appear among these plants, the large nuts floating upon the ocean having lodged on the shores and found the warmth and moisture well suited to their growth. Other kinds of palms and pineapples also grow on these reefs. 11. The Soil. — The soil is thin, seldom being more than six or eight inches deep, but as the top of the reef is somewhat open and honey-combed, the crevices become filled with the soil we have described, and they make good holding places for the roots of large trees. As the plants drop their leaves and decay, the soil is enriched little by little, and the island is fitted for the home of various ani- mals and birds, which in some mysterious manner find their way to these lonely spots far out at sea. In time our coral reef may become a beautiful tropical island fringed with waving trees and plants, and inhabited by man. 12. Atolls. — These circular reefs are called "atolls," and they seldom form complete rings. There is generally an opening into the lake on the side most sheltered from the wind. A safe harbor in mid-ocean is thus made, in which vessels may take shelter, but it requires an expert navi- gator to pass the perils at its entrance. In Fig. 28 is a pretty little coral island with ships in its lagoon. If a CORAL REEFS. 47 lake is entirely enclosed by the coral wall, it may in time be changed to fresh water by the rains that fall into it. 13. Theory of Coral Reefs. — Coral reefs often extend to a depth of many hundred feet below the surface of the ocean, and formerly persons were puzzled to know how they could have been formed in such deep water, as reef- buiiding corals do not thrive at a greater depth than one hundred and twenty or one hundred and eighty feet. This puzzling question was settled by the late Charles Darwin, who first showed that coral islands occur where there has been a gradual sinking of the bottom of the ocean. The theory is now generally adopted that as the growing reef rose in height, the foundation sank slowly, and in this way the upward growth was partly counteracted; consequently, the proper depth of water was secured, and the reef appeared to be stationary, whereas it was really growing upward. 14. When a coral reef rises above the surface of the 48 ANIMAL LIFE IN THE SEA AND ON THE LAND. ocean, we may know that the coral, which grew under water, has been lifted above the level of the sea by a rising of the ocean bed since the reef was formed. 15. Fringing Reefs. — "Fringing reefs" are those which extend along the shores of continents and islands. There are usually openings or breaks in fringing reefs directly opposite the mouths of rivers and fresh-water streams, as the corals cannot endure currents carrying mud or sed- iment. Perhaps the grandest reef to be found in any part of the world is the one extending along the north-east coast of Australia. It is nearly one thousand miles in length, and proves to us that the helpless coral polyps have played no trifling part in the formation of our earth. All they have accomplished has been done merely by their living and growing. CTENOPHOKA. 49 YIII. CTENOPHORA. DAINTY MORSELS FOR THE WHALES. SUB-KINGDOM, CCELENTEKATA : CLASS, ACTINOZOA. 1. Ctenophora. — Did you ever think how hard it would be to describe a soap-bubble to a person who had never seen one? It would even be difficult to paint a picture that would convey an idea of its delicate beauty. It will be quite as difficult to describe to you a class of animals almost as fairy-like as soap-bubbles, although they swim about in the ocean, and are honored with the high-sound- ing name of ctenophora. 2. How shall we Pronounce the Word? — At the first glance ctenophora may look like a hard word, but drop the "c," and you w T ill find it quite easily pronounced — "te-noph'-o-ra." Were it possible for you once to see these charming creatures darting about in their native sea-water, their name henceforth would have a pleasant sound, and even a pleasant look, recalling to your minds lovely images of floating balloons and fairy bubbles. 3. How shall we see Them? — Ctenophora are too small and inconspicuous to be seen at the distance we usually are from the surface of the ocean, so the best way to observe them is in a large glass jar. On a calm day a jar of water dipped from the surface of the ocean may contain some of these beautiful creatures, although perhaps several jar- fuls will have to be raised before the search is successful. 3 50 ANIMAL LIFE IN THE SEA AND ON THE LAND. 4. Transparency of the Ctenophora. — Upon looking close- ly at the little captives you will find them to be jelly-like, melon-shaped bodies, with bands running from end to end like the ribs on a melon. They are almost transparent, and if it were not for the prismatic colors that play upon Fi£. 29. — Ctenophora. their sides as they glide through the water we could scarcely see them. If the ctenophora sporting about in the jar should swim in between you and any object be- yond the jar, you can see the object distinctly through their transparent bodies. Fig. 29 shows the form of one of the ctenophora, but it gives no idea of its delicacy. CTENOPHORA. 51 5. The Soft Bodies. — The soft bodies of the ctenophora and their manner of life may remind you of jelly-fishes. Still, their structure is far more complicated, as we may observe through the clear substance of which the body is composed. When taken from the sea- water they lose their shape, and nothing is left but a film which is almost invisible. 6. Jelly-like Animals could Live only in Water. — The thought has perhaps already occurred to you that such animals as these, with jelly-like bodies, could live no- where but in the water. Many of them have no means of pursuing or of catching their prey, and they obtain only such food as is floated to them by currents in the water. 1. Food. — Although the ctenophora look so fairy-like, they devour a large number of animals, and they seem to prefer their own kindred. The mouth is at the upper end of the body, and when it is open, the food floats in and is quickly digested. In addition to the cavities nec- essary for digesting food, there is a set of canals within the body for the circulation of water. 8. How Ctenophora Swim. — The ctenophora swim about with exquisite grace, and yet they have no arms, no legs, no fins, to swim with. What need have they of any such organs ? Their cilia are quite sufficient (the word cilia, you remember, means eyelashes). Those eight stripes we see running from one end to the other in Fig. 29 are bands of muscles on which are arranged comb-like fringes of cilia, w T hich wave rapidly in the w r ater, and give to the animal its lively motions. Indeed, it seems as if the fairy- like creature could not keep still. How can it keep still w r hen these impatient cilia are striking the w T ater? They send the little thing round and round, darting up and 52 ANIMAL LIFE IN THE SEA AND ON THE LAND. down, till we wonder which way it will go next. The cilia are worked by muscles under the control of the ani- mal, and are to the ctenophora what oars are to a row- boat. 9. Study of Cilia. — These eight bands of cilia add greatly to the beauty of the dainty creatures. Their rapid motion separates the rays of light that fall upon them, and pro- duces down each band a flash of rainbow colors. In fact, the cilia are so important and characteristic a feature of Fig;. 30. — Cilia on the Gills of a Mussia. the ctenophora that we should do well to become per- fectly familiar with them. The appearance of these hair- like organs is much the same wherever they are found, and they show very distinctly on the gills of the mussel (Fig. 30). These gills are fringed with countless cilia, which under a microscope may be seen in rapid motion, producing a continual current of water in one direction. Their motion is regular, like that of the heart. The little plates forming the gill lie side by side naturally, and unless we looked very closely we might think the gills consisted of only one piece. The plates are pulled apart in the drawing to show the cilia more distinctly. CTENOPHORA. 53 10. It is interesting to notice the various uses of cilia in the different positions in which they occur. Sometimes, as in the ctenophora, they propel the animal by striking the water like a multitude of tiny oars. Sometimes they sur- round the mouth, "and by their incessant action produce a small whirlpool, into which the food is sucked." In other cases their office seems to be to supply the needful air by keeping up a continual current of water, which contains as much air as these animals need. On the other hand, we must not imagine that cilia are confined to the lower animals living in the water. They serve important uses even in our own bodies. For instance, the air-pas- sages leading to our lungs are lined with cilia, which are constantly lashing the air and beating back particles of dust and other impurities which it contains. Were it not for the cilia, these impurities would reach our lungs, and produce irritation there. 11. Food for Whales. — The beautiful ctenophora, idly sporting in the water, and seeming to have no aim but enjoyment, are far from useless, since they form the chief food of the Greenland whale. Do you not think these are dainty morsels for whales to feed upon ? There must, however, be a good deal of nourishment in their trans- parent bodies, for the whales grow enormously large and fat. No doubt it takes a great many ctenophora to make a meal for the monsters. Large shoals of them are met with in arctic seas, and as the whales swim through the water with their great mouths hanging open, they catch the ctenophora on their whalebone fringes, and swallow a mouthful at a time. 12. Their Abundance in the Ocean. — In certain parts of the Arctic Ocean the water is of a grass-green hue, and is quite opaque. It is commonly spoken of as the " green 54: ANIMAL LIFE IN THE SEA AND ON THE LAND. water," and its peculiar appearance is caused by the im- mense number of ctenophora it contains. These frolic- some little beings, living so thick and close as to color the water, are too small to be seen without a microscope. The Fig. 31. — Ctenophora and Phosphorescent Fishes. rose-colored idyia, another species of ctenophora, is three or four inches long. It sometimes occurs in such numbers as to tinge large patches of the sea with its rosy color. 13. Phosphorescence. — All the ctenophora are phospho- rescent. They are abundant on our own coasts, and are CTEXOPHORA. DO often left on the shore at low tide, yet their beauty can only be seen as they glide daintily through the water. The eggs of some species escape singly, others are laid in strings or masses of jelly, and the young ones hatch out in the same form as their parents. 14. Beauty of the Ctenophora. — A jarful of sea -water dipped from the end of a pier one bright summer day contained four ctenophora, and made a whole party glad for an hour. It was a great delight to watch these little creatures darting hither and thither, sinking and rising again, or resting on their oars, according to their own sweet will. Sometimes we could not see them at all, though we knew they were in the clear water before us; then a flash of bright color appeared, and we followed their devious course by their glit- ter and sparkle. 15. Pleurobrachia, — One of these captive ctenophora was smaller than the others, and more nearly spherical. It belonged to the spe- cies Pleurobrachia, which you will see represented in Fig. 32. This wtfs our especial favorite. At times it would throw out two long, slender tentacles, which were ornamented on one side with delicate tendrils. Upon some sudden fancy of the animal these tentacles were instantly drawn in out of sight, while at the next moment they were floating behind it for nearly half a yard. One might have supposed the exquisite creature was amusing itself by trying in how many different ways its tentacles could be curved and twisted Fiir. 32. — Pleurobrachia. 56 ANIMAL LIFE IN THE SEA AND ON THE LAND. IX. STAR-FISHES. SUB-KINGDOM, ECHINODERMATA : CLASS, ASTEROIDEA. 1. Favorite Haunts of the Star -fishes. — Those of you who go to the sea-shore in summer have perhaps discov- ered that star-fishes like rocky coasts the best. They are found most abundantly where the crevices between the stones afford good hiding-places for themselves and for the animals upon which they feed. They do not thrive upon muddy or sandy bottoms, and boys and girls hunt- ing for curiosities upon such beaches are often disap- pointed to find no star-fishes. 2. They spend most of their time creeping over the rocks, though they love to be where the tide will ripple over their bodies and keep them well supplied with sea- water, which they depend upon for their oxygen. Those poor, half-dead star-fishes which we sometimes see in a pitiful condition on the beach will often revive if placed in sea-water, or, if left on the beach, the next high wave may restore them by carrying them out to sea again. 3. How shall we Preserve them? — Our dried specimens are yellow, but when alive, star-fishes are of a dull-red color, sometimes tinged with purple. They seem plump and fat on being taken from the ocean, but they are only puffed up with water, and if you watch them closely you will see the water oozing out all over the back. No doubt STAR-FISHES. 57 you have learned how tedious and discouraging it is to attempt to dry star - fishes. You have perhaps been obliged to go home, as many before you have done, and leave them still drying in the sun. It may help you to know that a very good way is to dip them once or twice in boiling water before putting them in the sun or in a warm oven to dry. Fig. 33. — Under Side of Ray, showing the Hollow Tubes and the Limestone Plates of the Skeleton. 4. Broken Arms replaced. — Our common star -fish has five hollow rays or arms, extending from the centre like a star. If any of these rays are broken off, others grow in their places. It is a singular fact that these animals can break themselves to pieces, or throw off their rays, when they become alarmed. ■ 5. The Skeleton. — Star-fishes glide along smoothly, and without apparent effort. They bend their bodies into various shapes to fit the inequalities of the surface over which they creep, and in order to do this they require a movable skeleton. See how beautifully Nature has pro- vided for this necessity by forming the skeleton of thin limestone plates, so joined as to admit of slight motion. These plates are represented in Fig. 33, which is the under side of a ray, and the end having been broken off, we can see the two hollow tubes which the ray contains. 3* 58 ANIMAL LIFE IN THE SEA AND ON THE LAND. 6. The Upper Surface — The Madreporic Body. — Look now at the upper side of your star-fish, and notice the knobs and short spines with which it is covered. If the ani- Fig. 34. — Star-fishes (Lower One showing Under Side and Tube-feet). mal is alive we may see between these spines tiny forks, with two prongs that are constantly snapping. The use of the forks is not perfectly understood ; they some- STAR-FISHES. 59 times catch small prey, and they may also be useful in removing particles of matter that would otherwise choke up the pores on the surface. The first thing your bright eyes will discover is probably the round spot near the middle of the back and between two of the rays. That is called the " madreporic body," and it is an interesting object. Examine it with your microscopes, and try to think what those tiny holes can be intended for. It must Fie. 35. — Dining upon an Oyster. be a sieve. Yes, it is a sieve, admitting water into tubes which run to the end of each ray. During life the madre- poric body is bright-colored, and it strains all the water that enters the tubes, so there is no danger of their be- coming choked. 7. Singular Manner of Feeding*. — Now if we turn our star-fish over we shall find its mouth on the under side. This is an important organ, too, for star-fishes busy them- selves continually with eating. They are especially fond 60 ANIMAL LIFE IN THE SEA AND ON THE LAND. of live oysters and clams, and they have the oddest way of eating them. They turn their stomachs right out into the oyster shell, surrounding the soft body of the oyster, and sucking it up. When the star-fish feeds it not only bends its rays into a cup shape to hold on to its prey, like the one in the picture dining upon an oyster, but multitudes of tiny suckers spring up to help, and the prey finds escape impossible. Oysters generally close their shells so quickly in time of danger that we cannot under- stand why they should allow the sluggish star-fishes to catch them napping. It has been suggested that the star- fish drops into the shell some liquid which paralyzes the oyster, but this no one knows. So you see the star-fish, without any tools, is able to help itself to raw oysters. 8. Tube-feet. — The way in which star-fishes walk is also curious. It will repay you well to examine the next living star-fish you find, and notice the odd manner in which it glides along. On the under surface of each ray is a double row of hollow tubes, which squirm and grope around like a multitude of worms. As these are the or- gans by which star-lishes move, they are called tube-feet. They are lengthened and enlarged, much as the tentacles of sea-anemones are, by filling them with water. For this purpose each tube -foot is connected with a little round bag filled with water from the water-tube running down the ray. When the bag contracts it forces water into the foot, which reaches forward and attaches itself by a round sucker on the end to the surface over which the animal wishes to move. In this way one sucker after another is stretched out to cling to the surface, and as the suckers are shortened again by expelling the water, the body is dragged forward. Fig. 36 shows the interior of one of the rays. The tube-feet, g, are shrunken up quite short, STAR-FISHES. 61 which makes the water-bags, A, all the larger. Notice the mouth, a, the stomach, b, and the intestine, c. Fig, 36. — Interior of Ray. a, mouth; &, stomach; c, intestine; d, upper surface; e, limestone plates; /, ovary ; g, tube-feet ; h, \vater-ba<;s. 9. The double rows of tube-feet are set in a deep groove. In your dried specimens the tube-feet have shrivelled up and fallen away, and in the grooves you will probably see a number of delicate plates arranged side by side in two rows. These are called "ambulacral plates," and they are sufficiently far apart to allow water to flow out be- tween them from the water-bags into the tube-feet. No- tice this in Fig. 33. On the outer edge of the rays is a number of stiff spines. 10. Other Organs. — Star -fishes have a liver and intes- tines. Their organs do not lie wholly in the central por- tion, but extend into the five hollow arms. They also have nerves, which surround the mouth and pass down each arm, where they end in a red eye-speck. This arrangement gives to star-fishes five eyes. They are not perfect eyes, however, and it is probable that they can see but little. Star-fishes are said to be careful of their eggs, carrying them with the suckers near the mouth. 11. Destruction of Oysters. — The star-fish's fondness for fresh oysters is a serious matter to the oyster-grower, and 62 ANIMAL LIFE IN THE SEA AND ON THE LAND. causes him to lose large quantities of his valuable prop- erty. It is estimated that the damage every year to the oyster-beds between Staten Island and Cape Cod amounts to $100,000. Large numbers of star-fishes sometimes ap- pear suddenly and unexpectedly upon the shores. They seem to be washed in from the deep sea, and, settling upon the oysters, they begin their work of destruction, and consume many bushels in a short time. These attacks occur chiefly in the latter part of summer or early in the fall, and are much dreaded by the owners of oyster-beds. 12. Some Uses of the Star -fish. — The oysterman has learned the value of these destructive pests for manure, and those dredged from oyster-beds are now saved for fertilizing purposes. We might also attribute to the star- fishes a certain usefulness as scavengers of the ocean, since they eat all sorts of animal substances, dead as well as living, and do their full share towards keeping the waters pure. 13. Some kinds of star-fishes have long feathery arms, and are much more beautiful than our common ones which we have been studying. SEA-URCIIIXS. 63 X. kEA-URCHIXS. sub-kingdom:, echinodermata : class, echtnoidea. 1. Sea-urchins. — AVhat funny, prickly creatures the sea- urchins are ! A person might easily mistake them for green chestnut-burs scattered on the beach, and, glancing up hastily, he might almost expect to find the overhanging Fig. 3*7. — Under Surface op a Sea-urchin, showing Rows of Suckers among the Spines. branches of a great chestnut-tree. By this time, however, the prickly green things may have stretched out their pur- ple suckers and begun to drag themselves over the beach. This motion prompts us to place them among the animals. 64 ANIMAL LIFE IN THE SEA AND ON THE LAND. 2. How are they like Star-fishes? — We have seen the same method of travelling practised by our old friends the star -fishes, yet surely these round creatures can be nothing like star -fishes. But that is just what they are like, and I think we shall soon discover a close relation- ship between the two. We might almost say that the sea- urchin (Fig. 37) is a star-fish that has got up in the world, and, folding its rays together side by side, has concluded to live henceforth shut up in its beautiful round box. Fig. 38. — Shell of a Sea-urchin without Spines. 3. The Shells. — We sometimes find the empty white shells of sea-urchins which have lost their coating of prickles, or spines, as they are properly called. The shells are very elegant, being scarcely thicker than an egg-shell, and ornamented with rows of dots and knobs with open lace-work between. This shell is not one globular piece, as you might suppose, but it is made up of several hun- dred little plates exquisitely fitted together, and forming a true mosaic, as seen in Fig. 38. On the inside of the shell you can easily see the lines where these plates are SEA-URCHINS. 65 joined, and you will surely be charmed with the double rows of lace-work which divide the shell into five equal sections. Let us see what they mean. 4. Plan of the Sea-urchin. — If we should place a star- fish on the table with its mouth down, and bend its rays backward until they meet together on top, and the edges of the rays touch each other, we should have the gen- eral plan of a sea-urchin. Do not imagine that star-fishes ever do turn into sea-urchins. This is merely intended to show you the similarity of their structure. 5. According to this arrangement the double rows of perforated plates would represent the middle of the rays of the star-fish where the tube-feet are situ- ated, while the broad belt of knobs corre- sponds to the strip of spines on both edges of the ray. The mouth would be un- derneath, and you would of course look for the five eye-specks on the top where the Fig> 39 ._s E ction of a Sea-urchin. ends of the rays meet. a> m(ra th; c, stomach; d, intestine; o, anus; You will also find the madreporic body at the top, a little on one side. This small sieve, which is so interesting in the star-fishes, performs the same service for the urchin, and prevents the entrance of any sand or other solid substance into the five tubes that pass under the holes in the shell. Through these holes are pro- truded the double rows of tube-feet, just like those we v, heart ; /, madreporic body ; g, main water- tube ; p, tube-feet ; z, spines. 66 ANIMAL LIFE IN THE SEA AND ON THE LAND. have studied in the star-fish, and they are worked in the same manner. It adds much to the beauty and interest of the shell to know that these lovely fine dots are openings through which the tube-feet are supplied with water from inside the shell. In the diagram (Fig. 39) the madreporic body is shown at/, and the tube, g, carries water to supply the tube-feet and their little water-bags, which are shown at p. Sea-urchins move by means of their tube-feet, which may be lengthened so as to extend far beyond the spines. 6. Growth of the Shell. — The shell fits the animal ex- actly in its infancy, and must still serve it in old age, for urchins never cast off their coats as crabs and lobsters do. Being formed of many small pieces, the shell grows a little all over. Each plate is surrounded by living flesh. This flesh secretes lime from the sea-water and deposits it round the edge of the plates, thus increasing the size of the shell uniformly. After sea-urchins die the spines drop off; the shell is so frail that it too is soon broken, the plates falling apart. 7. The Spines. — Do not omit to look at the spines with your microscopes, and see what beautifully carved col- umns they are (Fig. 40). Falling about on the back of the urchin, they remind one of a sadly neglected grave- yard, with its tottering monuments. Each spine is hol- lowed at the end to fit a knob on the shell. This forms a perfect ball-and-socket joint, which is supplied with delicate muscles to move the spines. As the creature travels along, the spines are constantly in motion, and they look as if they too wanted to help. In some species the spines are very large, and are used for slate-pencils. We should think it quite luxurious to have such artistic pencils, yet many boys and girls in out-of-the-way places, especially where fishing -vessels bring home curiosities SEA-URCHINS. 67 Fig. 40. — Spine of Sea- urchin, MAGNIFIED. a, cross section. from foreign shores, have puzzled over their examples and written their copies with these elegantly fluted spines. 8. The Teeth.— Did you no- tice the white spot in the middle of Fig. 37, also the pointed beak near the top of Fig. 38 ? Both of these spots show the five white teeth which come together in a point, and may be extended beyond the shell just as they are in Fig. 38. You will ob- serve what a great step for- ward the sea-urchin has made. We have found noth- ing like teeth before in the lowly creatures we have been studying, and here is the ur- chin, armed with five hard white teeth, having sharp cutting edges like a rat's teeth. Each tooth has a separate jaw of its own, and is worked by its own muscles. This singular arrangement has at- tracted much attention, and from the shape of the jaws and teeth it is known as "Aristotle's lantern." 9. Internal Organs. — The sea-urchin is well supplied with organs (as we may see in Fig. 39) — the mouth, a, the stomach, c, the coiled intestine, d, and the anal open- ing, o — whereas our studies heretofore have been about animals with a simple sac for a stomach, and all the refuse of their food was returned through the mouth. This high- ly favored individual has also a heart, v, and blood-vessels, although the blood which passes through them is quite different from that of higher animals. ANIMAL LIFE IN THE SEA AND ON THE LAND. ,\ Fig. 41. — Sand-dollar. 10. Sea-urchins as an Article of Food. — The sea-urchins of the Mediterranean are larger than ours, and are used for food, either raw as we eat oysters, or boiled. They were a favorite dish with the ancient Greeks and Romans. Bunches of their eggs are also offer- ed for sale as food in the Italian cities. The eggs pass out of the shell through small openings near the madreporic body, and they are often seen on top of the shell, sur- rounded by spines which have been drawn together to hold them. 11. Echinoderm Defined. — Young people like to use the proper names for things, and now that we know all this about the sea-urchin we will give it its right name, the echinus. In your reading you will also meet with the word echinoderm, and it will give you pleasure to recognize it as an old acquaintance. Echinoderm means spiny-skinned. It is the general name given to star-fishes, sea-urchins, and their relations, most of which have prickly coverings. 12. Boring in Rocks. — The echinus has a curious habit of boring holes in hard rocks. It sinks in the hole for a considerable distance, and looks well satisfied with its snug retreat. It is not understood how the rock becomes worn away, unless it is by a rotary movement of the body. Constant dropping, we know, wears a stone, and constant turning and twisting may do the same. There is no doubt the hole is made by the animal which occu- SEA-URCHINS. 69 pies it, as it fits exactly, whether the occupant be large or small. 13. It is amusing to watch the echinus in shallow water drag itself along by its tube-feet, and sometimes hide itself by drawing together pieces of sea-weed and gravel. Fig. 42. — Keyhole-urchin. 14. Varieties of Sea-urchins. — In visiting a good museum you will be surprised to see how many different varieties of these creatures there are. Some species are flattened, and pass by the name of sand-dollars (Fig. 41), keyhole- urchins (Fig. 42), etc. During life the skeletons of these animals were covered with skin, and furnished with a fur- ry coat of little spines and small tube-feet. 70 ANIMAL LIFE IN THE SEA AND ON THE LAND. XI. CRINOIDS, OR STONE-LILIES. SUB-KINGDOM, ECHINODERMATA : CLASS, CItlNOIDEA. 1. Where Crinoids grow. — While examining the sea-ur- chins at the museum do not fail to hunt up the crinoids also. We shall have to be content with this way of study- ing crinoids, as the living ones grow on rocky beds in the deep ocean. They are obtained only by dredging, and few of us will ever have an opportunity to see them. 2. Why they are called Stone -lilies. — Crinoids are at- tached during the whole or a part of their lives to the sea- bottom by means of a jointed stalk which is so flexible as to bend freely in any direction. At the upper end of the stalk is the cup-shaped body, with its waving arms, which may be folded together like a flower-bud, or spread open like the petals of a full-blown lily. Swaying to and fro in the bright water, this curious animal closely resembles a flower tossed by a gentle breeze, and as it really has a hard skeleton throughout, c: stone-lily " is not a bad name for it. 3. Crinoids compared to Star-fishes. — Let us imagine a star-fish supported in this way upon the end of a long stalk, and we shall have a pretty good idea of a crinoid. In comparing the two we must invert the star-fish, how- ever, as the mouth of a crinoid is on the upper surface, whereas in the other echinoderms the mouth is underneath. CRINOIDS, OR STONE-LTLIES. 71 The tube -feet, like- wise, are on the up- per surface of the arms, but they are not used for travel- ling about as the tube - feet of other echinoderms are. The grooves contain- ing them are covered with cilia which cre- ate currents of water towards the mouth, and carry to it the minute plants and animals upon which the crinoid feeds. 4. Skeleton of Cir- cular Plates. — Like star - fishes and sea- urchins, these cousins of theirs secrete lime to form a solid frame- work for their bod- ies. The lime is de- posited in circular plates, which are sur- rounded and held to- gether by living flesh, so that they bend ea- sily. You can detect these circular plates in any part of the ac- Fig. 43. — A Living Crinoid. West Indies. 72 ANIMAL LIFE IN THE SEA AND ON THE LAND. conipanying picture. Indeed, crinoids may be known by the little rings of which they are composed. 5. Free Swimming Crinoids. — In some crinoids, as the Comatida, or feather-star, the animal is fastened to the ground only when young. Later in life it drops from the stalk, and is free after this to travel about. It can swim through the water ; still, it prefers to remain quietly set- tled on some stone or sea -weed, waving its feathery, bright-red arms while it feeds upon the little animals floating around. It now resembles a star-fish more than ever, though it moves only by means of its flexible arms. 6. An Ancient Family. — The family of crinoids is very ancient, and was perhaps at one time the most numerous family which inhabited the sea. Like some other old families, it has almost died out. There are but few spe- cies now living, and two or three of these have been only recently discovered by scientific explorers while dredging the deep waters of the Caribbean Sea and the Atlantic Ocean. 1. Fossil Crinoids. — Fossil remains of crinoids are abun- dant in rocks, showing that in past ages they must have lived in great numbers. In France large beds of rock are formed of their remains, and the same is true of many other parts of Europe and North America. The circular plates of the crinoids were so loosely held together by flesh that when the animal died they fell apart, and these little disks which are now found in the rocks look like button - moulds ornamented with beautiful patterns and markings. 8. See how the crinoid stems are piled upon each other in the limestone rock (Fig. 44), and notice the little hole in the middle of each. Their arrangement in the rock (Fig. 45) is much more orderly. No wonder that such CKINOIDS, OR STONE-LILIES. 73 fine old crinoids as this should have been mistaken for petrified flowers. 9. How Fossils came to he in the Rocks. — Perhaps you will wonder how animals can be embedded in hard rocks. Fig. 44. — Crinoidal Limestone. To understand this we must remember that many of our rocks are formed of sand or mud, which has become hard from the constant pressure of other layers of sand and mud that have accumulated above them. Most of these layers were formed underneath the sea. The rocks must have been in this soft condition when the animals died and were buried in them. As the rocks hardened, the solid parts of the animals were preserved in a stony bed, the hard rock fitting closely into every crack and cranny. When these rocks are split open we sometimes find the remains of the animal on one side of the crack, and a perfect impression on the other. These petrified remains are called fossils, and they tell us a fascinating story of the curious animals and plants that lived long ago. 4 74 ANIMAL LIFE IN THE SEA AND ON THE LAND. 10. Records of our Earth's History. — The true nature of fossils, and the causes which placed them in solid rocks, interested the poets and philosophers long before ' the Christian era. It is only within the last century, how- ever, that they have been accepted as records of the his- tory of our earth. There are many animals now entirely extinct of whose existence we should know nothing but A Fossil Ckinoid. for their fossil remains. These relics of the past tell also of great changes from heat to cold in certain parts of the earth. For instance, the bones and teeth of ele- phants, rhinoceroses, and other animals that require warm climates are found in Siberia and in other cold countries, which shows that the polar regions were once much warmer than they are now. Again, on the other CTUNOIDS, OR STONE-LILIES. 75 hand, remains of reindeer are found in Southern Europe, indicating extreme cold at another period in the earth's history. 11. So you see these fossils have wonderful secrets to tell. Strange, old-fashioned secrets, for the formation of the rocks has been very slow, and the animals buried in them must have died thousands of years ago. Oinoids and corals and shells which live only in the ocean are found in a fossil condition in the interior of the dry land, prov- ing beyond a doubt that these parts of our earth must at one time have been beneath the sea. 12. Is it not a lovely thought that these delicate crinoids which beautified the ocean long before we were here to admire them are not utterly destroyed, but that some of their skeletons have been preserved and are waiting for us in the gray old rocks, if only our tastes are simple and cultivated enough to find them out? '6 ANIMAL LIFE IN THE SEA AND ON THE LAND. XII. SEA-CUCUMBERS. SUB-KINGDOM, ECIIINODERMATA : CLASS, HOLOTHUROIDEA. 1. The New England Coast favorable for Growth of Sea- animals. — The shore of Maine, you will remember, is very uneven, being broken by a succession of sharp promonto- ries and quiet bays, and skirted with a fringe of lovely islands. Here is an endless variety of bold rocky cliffs, of secluded caves and quiet little pools, with the pleasing surprise of occasional short sandy beaches. We can scarcely imagine a shore better fitted than this to suit the various tastes of the sea-creatures, and our search here is pretty sure to be rewarded by finding sea-anemones, star- fishes, sea-urchins, sea-cucumbers, etc., besides a variety of shell-fishes. Sea-weeds also grow in abundance, coloring the water with their beautiful tints. 2. This is true of the New England coast as far south as Cape Cod, while below that point the sandy beaches of the Atlantic shore are not favorable for the growth of these animals. In addition to the loose sand which is washed up on the beach, the great number of rivers emp- tying fresh-water into the sea renders it still more unfa- vorable for their abode. 3. Sea-cucumber. — As found on the beach, a sea-cucum- ber would remind you of a leather bag, somewhat worm- like in form, with no hard shell, and marked with rows of warts down the sides like a cucumber (Fig. 46). The skin SEA-CUCUMBERS. 77 is tough, yet it may expand and contract in such a way as to give these animals the curious power of changing their shape. Fig. 46. — Ska-cucumbers (Holothukians). 4. Changes into Odd Shapes. — Upon watching the move- ments of a sea-cucumber you will be amused at the odd shapes into which it changes. It sometimes lengthens out its body like a worm, then drawing itself in tightly around the mouth, it swells out the other end of the body like a jug. Suddenly, tiring of this freak, it can make an hour-glass by contracting its body, as if a string were tied around the middle of it, with bulges above and below. 5. Feathery Tentacles around the Mouth. — The tentacles of a sea-cucumber form a feathery fringe around the mouth. Their number is usually ten, and they have the same curious power of changing their shape that we have noticed in the body of the animal. The mouth may be distinctly seen in Fig. 47, which represents another spe- cies of sea-cucumber. It opens into a throat leading to the stomach. The long intestine passes to the other ex- tremity of the body. 78 ANIMAL LIFE IN THE SEA AND ON THE LAND. 6. Sea-cucumber an Echinoderm. — From the general ap- pearance of the sea-cucumber you will scarcely suspect that it is one of the echinoderms, but, after watching it creep over the rocks, you can see the relationship. The tube- feet steal out noiselessly from the wart-like spots, as seen in Fig. 48, and the sea-cucumber travels just like a sea- urchin. The tube- feet are arranged on five muscular bands running from end to end, and dividing the body into five seg- ments. The spaces between the tube- feet correspond to the spaces which are covered with spines in the sea - urchin. One species of sea- cucumber has the tube-feet all collect- ed on the under side of the body (Fig. 49). It is called a " sea- orange" probably from the rough rounded markings on its surface. In those species which have no tube-feet the animal drags itself along by the aid of anchor-shaped spicules scattered through the skin. 1. Resemblance to other Radiates. — The madreporic body is not on the outer surface, as it is in other members of the family. It opens upon a little canal in the interior, which supplies the tube-feet with water. Although hidden from Fig. 47. — Sea-cucumbers. SEA-CUCUMBERS. 9 our view, this tiny sieve niters the water perfectly, and allows no irritating particles to enter the tube. The only resemblance to the other Radiates which we detect in these animals is in the arrangement of J*b 6v their tentacles, their tube -feet, and muscular bands. 8. Castaway s^ih Organs Replaced. <$h — The sea-cucumber does not break itself to pieces as the star -fish does, but it has a pecul- iarity quite as remark- able : when alarmed it throws away various organs from the inte- rior of the body, and, strange to say, these castaway organs are soon replaced by oth- ers. 9. Holothurians — where found. — Sea-eu- i 7 ? ^ 7 Fig. 48. — A Sea-cucumber (Pentacta Fron- cumbers, or hocot/iu- ° D0SA \ v Hans, as they are prop- erly called, are most abundant in tropical seas, where they lie in the mud, or in shallow water, with their tentacles floating in expectation of prey. These creatures, as found on our shores, with their tentacles snugly stowed away, have no pretensions to beauty. One species, however, 80 ANIMAL LIFE IN THE SEA AND ON THE LAND. from the Pacific Ocean is described as being much hand- somer than the rest of its kind. The body is as trans- parent as glass, and of a lovely rose-color, with fine white stripes running from one end to the other, and crowned with a wreath of pure white tentacles. 1 0. An Article of Food.— Anoth- er kind of sea- cucumber, called the trepang, is a favorite article of food with the Chinese. Many thousand junks are engaged in the trepang fisheries in the Indian Ocean. The trepangs are caught with a harpoon as they creep over the rocks and corals, or, when the Fig. 49. — Sea-orange. SEA-CUCUMBERS. 81 water is shallow, they are brought up by divers. While yet alive the animals are thrown into boiling sea- water, and stirred with a long stick. After being boiled and flattened with stones, the Malay fishermen spread them on bamboo mats, where they are dried and smoked ; then they are packed and shipped to the Chinese market. 11. Jelly Lumps in the Sea are often undeveloped Young.— In strolling on the sea-shore we often find little lumps of clear, transparent jelly left there by the retreating tide. Many of these jelly lumps are the undeveloped young of the class of animals we have been studying ; and if some time you should place a number of them in sea-water, and change the water frequently, you may have the pleasure of watching their development, and see what special forms they assume. These animals produce young ones in great abundance. It is necessary they should do so, or the race would soon die out, as they are devoured in such num- bers by fishes that only a small proportion of them live to maturity. 12. Animals Preying upon Others. — The sea contains myriads of animals that prey upon each other, the larger ones eating the smaller ; and we can form but little idea of the amount of life continually sacrificed for the support of that which remains. It seems almost marvellous that any of the delicate little ones should escape the hungry hordes that pursue them in this eager struggle for life. 4* 82 ANIMAL LIFE IN THE SEA AND ON THE LAND. XIII. EARTH-WORMS. SUB-KINGDOM, ANARTIIROPODA : CLASS, ANNELIDA. 1. The Work of Earth-worms. — Who would have thought the little earth -worm had any work to do in the world, or was of other use than to bait fish-hooks ? Yet it has an important part to perform, and we are now told that the present fertile condition of the earth is largely due to the action of earth-worms. 2. If this is the case, we must look at these industrious workers more carefully. Having selected a fine large specimen, let us put it on a piece of white paper, where it will show to advantage. 3. A Land Animal. — This is the first animal we have examined which lives upon land. The simplest forms of life are always found in water, but from this point in our studies we shall sometimes take our specimens from the land, and the boys and girls all over the country will have an equal chance to obtain them. Even those who live in large cities can procure earth-worms. 4. Study of the Illustration. — Let us study for a moment the illustration of an earth-worm that we have here. The worm itself is shown at Fig. 50, a ; b is a small part of it magnified so as to show the bristles pointing backward. The egg of the worm, c, is curiously constructed, having a valve at one end. In d we see the young worm, which has opened the valve and is coming out of the egg. EARTH-WORMS. 83 5. The Body made up of Segments — Articulates. — The body of the worm tapers towards each cud, so that we can scarcely tell the head from the tail un- less we watch a worm as it is creeping. Notice all those little rings across the body, and see how they slip in and out of each other as the worm moves. These rings can be drawn so close to- gether that a large worm will some- times make itself very short. Does this creature look like a Radiate? Certainly it does not, and we will now learn that all animals which have the body made up of rings or segments extending crosswise belong to a class called Articulates. 6. The Bristles. — The earth - worm contains from one hundred to two hundred of these rings, each of which is furnished with four pairs of bris- tles pointing backward. You can easily feel them with your fingers. The bristles assist in crawling, and prevent the worm from slipping back as the rings are contracted and expanded. Still, the worm can creep back- ward when it desires to, and you may have noticed how rapidly these timid animals draw back into their holes. 7. Organs. — Earth-worms have no distinct head or eyes. The mouth consists of two lips, and it has neither teeth nor tentacles. The semi-transparent body will enable you to see the food canal, extending from the mouth through the whole length of the worm, and enlarged in two places to form the crop and gizzard. Grains of sand and small Fie:. 50. — Earhi-worm. 84 ANIMAL LIFE IN THE SEA AND ON THE LAND. stones are often found within the strong gizzard, where they probably act as millstones in helping to grind the food. Birds, we know, are in the habit of swallowing stones for the same purpose. 8. Blood-vessels— Ganglia. — We find no heart in these lowly creatures, but in its place a set of blood-vessels, which contract in such a way as to force the blood from the tail towards the head. It is supposed that earth- worms breathe by tubes opening upon the external sur- face of their bodies. Each one of the rings is supplied with a pair of nervous ganglia. This is true of all the Articulates. In animals of this group, each segment of the body is supplied with its own nervous ganglia. Ganglia are nerve-centres which consist of a mass of nerve -cells sending out nerve-fibres to other parts of the body. 9. Food of Earth-worms. — Worms live in burrows in the ground, and in making them they swallow an almost in- credible amount of earth, out of which they take all the nourishing matter. They do not confine themselves, how- ever, to this coarse diet, but feed upon leaves and stems, from the edges of which they suck off little bits, having first drawn them into their burrows for a distance of two or three inches. Leaves are also dragged in for plugging their burrows, and when they cannot get leaves for this purpose they sometimes pile up heaps of stone to close the entrance. This work is all done during the night. 10. The Burrows. — The burrows are often lined with a layer of fine earth, Avhich seems not only to strengthen the walls, but to form a smooth surface for the worm's body. At the bottom of the burrow there is generally an en- larged chamber which contains small stones, and here the worms pass the winter rolled up two or three together in a ball. earth:- wo rms. 85 11. Castings made by Earth-worms. — Now, if we want to know what becomes of the earth which is swallowed by worms, we have but. to remember the rounded, worm-like heaps of earth called " castings " which are so thick among the grass, and on the untrodden parts of paths and drives, or in the flower-pots when a few worms have been dug up with our favorite house-plants. When a worm comes to the surface to empty its body it backs out of its hole, and ejects the earth which it has swallowed in spurts, first on one side, then on the other, until a little heap is formed, which hardens in drying. It is estimated that the quan- tity of fine earth thus carried to the surface in the course of a year would in many places form a layer one-fifth of an inch in thickness, amounting to a weight of more than ten tons on each acre. 12. Vegetable Mould the Work of Earth-worms.— Have you ever noticed the layers of different-colored earth that are exposed in digging a well or a cellar ? The upper lay- er, you may remember, is mostly of a rich dark color. It consists of fine soil two or three inches deep, which has been sifted of stones and coarse materials, and is spoken of as "vegetable mould." This fertile layer is the work of earth-worms. 13. Charles Darwin estimated that th© whole mass of vegetable mould which is spread over the surface of the earth passes through the bodies of worms once every four years, and in this way fresh masses of earth are constantly exposed to the influence of rain and wind. Worms also do much to enrich the soil by the great number of leaves and twigs drawn into their burrows. 14. "The bones of dead animals, the harder parts of insects, the shells of land mollusks, leaves, twigs, etc., are before long all buried beneath the castings of worms, and 86 ANIMAL LIFE IN. THE SEA AND ON THE LAND. are thus brought in a more or less decayed state within reach of the roots of plants." 15. The Earth Ploughed by Worms.—" The plough is one of the most ancient and most valuable of man's inven- tions ; but long before he existed the land was, in fact, reg- ularly ploughed, and still continues to be thus ploughed, by earth-worms. It may be doubted whether there are many other animals which have played so important a part in the history of the world as have these lowly or- ganized creatures." The corals, indeed, have done more conspicuous work in constructing great reefs and islands, but these are mostly confined to the tropical zones. 16. How Stones and Pavements Disappear. — It is no new discovery that pebbles and cinders and even large stones lying on the ground in a few years disappear. Neglected and unused pavements also become covered with soil, much of which has been raised by these busy little work- ers. Such every-day wonders escape the attention of most of us, but Charles Darwin, while pursuing his studies and observations upon various subjects, still found time to no- tice the worms. He and his sons watched them for more than thirty-five years before he published the book which gives these interesting facts. 17. Destruction of Worms by Birds. — He says that worms often lie motionless for hours just beneath the mouth of their burrows, so that by looking closely their heads may be seen. If the earth or rubbish over the burrow be sud- denly removed, the worm retreats rapidly. This habit of lying near the surface leads to great destruction. At cer- tain seasons of the year the thrushes and blackbirds draw large numbers out of their holes. Watch a robin some morning hopping over the lawn, and see how it pecks, and pecks, at some object, finally bracing itself upon its EARTH-WORMS. 87 tail, and pulling with all its might, as if determined to draw out its victim ; but the worm holds on so tightly by- its short bristles that it is no easy matter for the robin to capture it. 1 8. Found all over the World.— Earth-worms exist all over the world, in cold countries as well as in warm ones, and even in small islands far out in the ocean. They require some moisture, and during very dry weather, or when the ground is frozen, they retire to a considerable depth. 19. Large numbers of worms are often found dead on the pavements after a heavy rain. As earth-worms like moisture, it is scarcely probable these have been drowned. Darwin suggests that they were already sick, and that the flood may only have hastened their death. 88 ANIMAL LIFE IN THE SEA AND ON THE LAND. XIV. CEABS. SUB-KINGDOM, ARTIIROPODA : CLASS, CRUSTACEA. 1. Crabs. — Crabs are curious creatures. At the first glance we can scarcely tell which is the head. Notice the position of the eyes (Fig. 51), and that will settle the question. Walking, as they do, forward, backward, and even sideways, with equal ease, it seems as if they too might be slightly puzzled about their formation, and so, CRABS. 89 not stopping to decide which part is intended to go fore- most, they dart off on a venture, and in the oddest manner possible. 2. Abundant on the Sea-shore. — They are so abundant on all our sea-shores that we rarely lift a bunch of sea-weed or poke among the rubbish there without disturbing their haunts, yet they scramble off and hide in the sand so quick- ly that we are not much wiser for their discovery. Let us pick up some cast-off shell and make a closer examina- tion. 3. Cephalo-thorax. — The bodies of higher animals con- tain three principal cavities — the head, thorax, and abdo- men. In crabs, on the contrary, the head and thorax are so closely united that we cannot distinguish them, and they are covered by the same shell. The proper name for a head and thorax thus united is "ceph-a-lo-thorax." 4. Two Principal Parts. — A crab, consequently, has two principal parts — the cephalo-thorax and the abdomen — each containing a number of segments of its own. To the cephalo-thorax are attached five pairs of jointed legs. The front pair are much larger than the others, and form the claws. The abdomen consists of six segments ; but it is small and inconspicuous, being folded under the cephalo- thorax. 5. Stalked Eyes. — The compound eyes of crabs are on long stalks, and they may be turned in different directions or folded back into little grooves in the shell. 6. The Gills. — Crabs breathe by gills, which are leaf- like plates so situated as to be readily bathed with water. They contain a dense net-work of blood-vessels, through whose thin walls the oxygen in the water finds its way and mixes with the blood to purify it. The crab's heart consists of a single contractile sac. 90 ANIMAL LIFE IN THE SEA AND ON THE LAND. 7. How Crustaceans shed their Shells. — Crabs are often spoken of as crustaceans. The name will at once suggest animals having a hard crust. As this crust contains a number of pieces exactly fitted to one another, it has been compared to the armor worn by soldiers in olden times. The manner in which it is shed during the growth of the crab is curious and interesting. This hard shell never in- creases in size; therefore, as the crab grows its shell be- comes too small, and is cast off. The discarded shell has the eye-stalks and legs attached, and looks like the perfect animal. When the proper time for this change arrives, the body shrinks away from the shell, separating from it at all points, and the animal works its way out of its old case. The exhausted creature now remains quietly in some secluded place, increasing rapidly in size, until the soft skin again hardens into a new shell. 8. This is a painful and perilous experience for the poor crabs. Occurring as it docs several times in the summer, their weak and unprotected bodies fall an easy prey to their enemies, and they are often devoured even by other crabs which happen to be in better plight. Now it is that they are known as " soft-shelled " crabs. 9. Destroyed by other Animals. — Crustaceans, when ful- ly coated with mail, are strong and destructive, fighting among themselves as well as with other animals. They eat any small creatures that come in their way, whether living or dead. On the other hand, they themselves are destroyed by larger animals, and crustaceans form a great part of the food of star-fishes, sea-urchins, mollusks, and many kinds of fishes and birds ; consequently, great num- bers of them are killed before reaching their fall size. To protect the race from destruction by this loss of life, all crustaceans produce a large number of eggs. CRABS. 91 £31 -Early Form of thk Crab. 1 0. Young Crabs unlike the Old Ones. — Young crabs (Fig. 52) are so unlike the full-grown ones that natural- ists formerly thought they belonged to a different class of animals. While yet very small they rise to the surface of the water, and swim about freely, until, after pass- ing through several changes, the body be- comes large and heavy Fio . 52 towards the head, and the young crabs, losing the power of swimming, sink to the bottom, where they hide for a time. As they gain in size and strength, and are ready to begin their new manner of living, they creep towards the shore, and most of them pass the rest of their days in shallow water among the sea-w T eed. 11. Where they Live. — In the tropics some species live in the fresh water of brooks and rivers. Others live in the shades of damp forests ; but, when breeding-time ar- rives, they visit the sea-shore to deposit their eggs. The land -crabs of Jamaica even live on the mountain -toj)s, yet every year they yield to a longing for their old home, and come down to the shores of the Caribbean Sea to lay their eggs. This duty performed, they return again to the mountains. 12. The Hermit-crab. — The hermit-crab (Fig. 53) is al- ways an object of interest. Unlike most other crustaceans, it has no shell to protect the soft body, and a tempting morsel is thus exposed. The hermit, conscious of its weak point, seeks shelter by taking possession of some spiral shell in which to place its soft abdomen. The hard claws 92 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fiff. 53. — Hkumit-ckau. and the first two pairs of feet generally hang out over the edge cf the shell, which henceforth moves about upon the crab's back as if the two belonged together. The shorter hind -feet are roughened, thus en- abling the crab to hold I on to the inside of the shell, to which it clings so tightly that it will sometimes allow itself to be torn in pieces rather than quit its hold. 13. As the hermit grows it needs to hunt up a larger home, and it may be seen creeping along the shore, exam- ining and turning over shells to select one, often trying on several before it is suited — much as a boy might try on several pairs of boots before he is fitted exactly. Should a hermit fancy the shell of some living snail, it would not hesitate to kill and eat the owner, and then coolly take possession of the shell. Two hermits are sometimes found fi^htin^ for the same shell. 14. Fiddler-crabs. — Fiddler-crabs (Fig. 54) have one claw much larger than the other, and as they walk sideways they hold up the large claw in a threatening manner. They dig holes in the mud to live in, and they enter these homes with extreme caution. Running quickly to the en- trance, they pause a while, turn their stalked eyes in every direction, and then slip suddenly in. They are not easily caught, for they dart into their holes quickly when alarmed. 15. Effect of Use upon an Organ. — The fiddler-crab is a good illustration of the effect of use upon any one organ. CRABS. 93 The large claw so peculiar to this group belongs only to the males, who are great fighters. They use the large claw in their combats, which fact accounts for its increased size. The more peaceable females have no need of so powerful a weapon, consequently they do not possess this striking pe- culiarity of their mates, and, on the contrary, have small weak claws. Fi£. 54. — Fiddler-crab. 16. Pea-crabs. — Many of you have seen the little round crabs that live in oyster-shells. These pea-crabs, or oys- ter-crabs, as they are called, are considered a delicacy, and are sometimes collected and sold by the dozen. Having no hard covering, they always take up their abode within the shell of the oyster or some other bivalve. They are not prisoners within the shell, as they venture out into the water sometimes, and return again when they wish. 17. They are said not to annoy the oyster in the least, or to deprive it of its food, since they eat certain small animals which float into the shell, but which the oyster never feeds 94 ANIMAL LIFE IN THE SEA AND ON THE LAND. upon. Strange to say, it is only the female that shuts her- self up within the narrow limits of an oyster-shell. The male is much smaller, and frolics about on the surface of the sea. 18. Horse-shoe Crab. — Going from one extreme to the other, let us now notice the horse-shoe-crab, or king- crab, as it is also called, because it is the largest of all our crabs. This sin- gular dark-brown crab, with a long, stiff tail, is very different, as you will see, from ordinary crabs. It partly buries itself in the sand to hunt for its food, and the cast-off shells of all sizes, from cute little ones that have been shed by tiny infants to those of the full-grown king-crab, are often found on sandy beaches. An egg of the king-crab, one-third larger than life, is shown in the illustration (Fig. 55). Several days before the egg hatches the young crab may be seen sporting about within the transparent shell of the egg. Fie:. 55. — King-crab LOBSTEKS. 95 XV. LOBSTERS. SUB-KINGDOM, AltTHROPODA : CLASS, CRUSTACEA. 1. Lobsters and Crabs Compared. — Lobsters, as well as crabs, have the head and thorax united, forming a ceph- alo- thorax. The compound eyes are on long, movable stalks. Behind these are two pairs of jointed antennas or feelers. But near the mouth are five pairs of "jaw-feet," which we do not find in crabs ; these, and some other ad- ditional organs, point to a difference in their manner of living which we shall now consider. 2. As lobsters live entirely under water, they breathe only by gills, which are richly supplied with blood. The gills are situated in a cavity under the body, and each plate of the gills is attached to one of the legs. A current of sea-water is kept passing over the gills, partly by the movement of the legs, and partly by a spoon -shaped ap- pendage to the second pair of jaw-feet, which constantly bales out the water from the gill cavity. 3. The Claws. — A pair of true walking legs is attached to each of the last five segments of the cephalo-thorax. The front pair of legs forms the claws ; these are very large, and are armed with strong pincers. One claw has sharp teeth for tearing food ; the other has rounded teeth, and is used as an anchor to hold on to fixed objects. Lobsters are so quarrelsome that fishermen, before sending them to market, often fasten their claws open with plugs 96 ANIMAL LIFE IN THE SEA AND ON THE LAND. to prevent their fighting and injuring each other. Like some other animals we have studied, lobsters can throw off their own legs and claws when wounded or alarmed. New ones grow in their places, but we often see lobsters with limbs that do not match each other in size. 4. The Swimmerets. — Lobsters are great swimmers, and they are w T ell suited to this favorite sport. The large abdomen consists of six segments, each bearing a pair of paddles called "swimmorets," while the body ends in a broad fin or "telson." Each appendage is attached to a segment of its own, and it is thought by some naturalists that the jaw-feet, antennae, and eye-stalks are all modified limbs attached to their appropriate segments. 5. How Animals are Fitted to the Life they Lead. — It is interesting to notice how well every animal is fitted to the life it leads. The lobster by striking its powerful tail upon the water takes a long spring, and in this way the abdomen is a great assistance in swimming. The claws are also constantly used to catch the prey and to defend the animal, hence both the claws and the tail are large and muscular. These two organs we know contain the chief eatable part of the lobster. The crab, on the other hand, living upon the sandy bottom of the ocean, and among the rocks on the shore, is accustomed to walking or running, and as the abdomen is not needed for swimming pur- poses, it seems to have dwindled away to a mere apology for a tail, which is snugly tucked up beneath the cephalo- thorax. This same thing happens everywhere in nature. An organ that is no longer needed or used, shrivels in size and sometimes wholly disappears. 6. Internal Organs. — We must next know something of the internal organs of the lobster. A short oesophagus or gullet leads from the mouth to the stomach. The stomach LOBSTERS. 97 is very large, and contains curious pieces of cartilage to which strong grinding teeth are attached for crushing the food. These teeth are often called the "lady in the lobster." The large liver is of a dark-green color, and the heart consists of a single contractile sac, just back of the head. Fig. 56. — Lobster (IIomarus Vulgaris). V. The Lobster outgrows its Shell. — The legs, antenna?, and even the eye-stalks of lobsters are incased in a hard shell, which, like the crab's shell, never increases in size ; consequently, as the animal grows larger, its shell becomes too small. At such times the lobster loses its appetite, and hiding in some secluded corner, grows weak and thin. In this way the body shrinks from the shell. The shell then splits open, and after a good deal of screwing and twist- ing, the soft, tender body creeps from its outgrown case, drawing out with it legs, claws, eye-stalks, and all. 8. Forms a New Shell. — How weak and defenceless the 5 98 ANIMAL LIFE IN THE SEA AND ON THE LAND. poor creature must feel with no coat of mail! It seems aware of the danger of being eaten by its hungry neigh- bors, so it remains out of sight. The lobster now fills its body with water and swells out as much as possible, and the soft skin, which is covered with a sort of glue, hardens to form a new shell, fitting tightly over every part just as the skin did. 9. Color. — The natural color of lobsters is a greenish- black, but it changes to a bright red in boiling. The females are sometimes found with large masses of eggs fastened to the swimmerets. The young ones are hatched with the same form as their parents, and they do not pass through the changes we noticed in young crabs. 10. Manner of catching Lobsters. — Lobsters choose the deep, clear water along rocky coasts for their dwelling- place, and on account of the delicacy of their flavor, they are caught in large numbers for food. A common way of catching them is by the use of " lobster pots." These are wooden cages with a funnel-shaped hole in the top, through which the lobsters can easily enter, but cannot so easily get out again. The pots are sunk in the water and marked by buoys. Great quantities of lobsters are caught on the coasts of the British Isles, and are often kept in perforated chests floating on the water until they are sent to market. BARNACLES. 99 XVI. BARNACLES. SUB-KINGDOM, AKTHROPODA : CLASS, CRUSTACEA. 1. Barnacles form a Coating on Rocks. — Boys and girls who have been to rocky sea-coasts may have noticed a dull white coating upon the rocks after the tide has gone down. If they have given the subject much thought, they have probably discovered that on the cliffs this coating forms a strip reaching only to high-water mark. 2. At first we may think the rocks quite disfigured, but so great is the charm which living beings have for us that we shall become interested at once upon learning that this rusty covering consists of acorn- barnacles. 3. Shells closed at Low Tide. — Any rocks that stand be- tween high and low water mark may be chosen as the resting-place of these curious creatures. When the rock is left high and dry above the water there is nothing attractive about the barnacles. Their shells are tightly closed (as seen in Fig. 57), and they appear per- Fig. 57. — Acorn-barnacles. 100 ANIMAL LIFE IN THE SEA AND ON THE LAND. fectly lifeless ; but watch them when the tide comes in, and they will show signs of returning activity. 4. Manner of Feeding. — With the first welcome wave that reaches their resting-place you will see the valves within the acorn open, and a delicate feathery cluster of arms will be thrown out of each barnacle, as in Fig. 58, and then sud- denly disappear. This movement is repeated every few seconds with great regularity, and makes a cur- rent in the water, carrying towards the mouth small floating bodies on which the barnacle feeds. 5. The shell consists of two parts, one within another. The outer one is composed of several plates, open at the top; within it is a conical movable lid, the plates of which are opened and closed every time the arms are thrown out. In this way barnacles fish vigorously, as if they understood that two tides mean but two meals during the day, and consequently they must make the best use of them. 6. This fishing is a graceful operation, and if you should find a large rock covered with barnacles, and bathed with clear sea-water, you will soon be fascinated with watching their motions. As the valves at the top of each cone open, twelve pairs of light, feathery arms are thrown out and drawn in again with unvarying precision. 7. Young Barnacles more highly developed than Full- grown Ones. — Young barnacles, when first hatched, are active, restless creatures, swimming about like young Fig. 58. — Acorn- barna cle, with Arms ex TENDED. BARNACLES. 101 Fig. 59. — Body op GOOSE-JBAUNACLE. crabs, but as they grow older they attach themselves to rocks, shells, drift-wood, sea-weed, sponges, turtles, or even to jelly-fishes. The head is firmly glued to these objects by a cement which the animal secretes. The rest of the body is free, and can be extended be- yond the shell. Fig. 59 shows the body of a barnacle as it looks within the shell. 8. While young, and frolicking about in the water, barnacles have two well- developed eyes, but these dwindle away when the animal settles for life, and they finally disappear altogether. The shelly covering now grows, and henceforth bar- nacles are quiet, orderly individuals, nev- er moving from the spot which they have chosen as a resting-place unless this hap- pens to be upon a living animal or some floating object. So you see barnacles are really more highly developed in youth than they are later in life. Be- fore growing into perfect barnacles they have, parted with their sight, and with the power of moving or swimming from one place to another. 9. Clinging to Vessels. — Barnacles are found in all seas. They sometimes settle so thickly on the huge Greenland whale as to hide the color of its skin. They are also found clinging to the hulls of vessels in such large masses that the movement of the vessels through the water is re- tarded. These barnacles grow rapidly, and ships which start upon their voyages freshly painted have sometimes been obliged to put into port in order to have the bar- nacles scraped from the hull. 10. Goose-barnacles. — The goose-barnacle (Fig. 60) dif- fers from the acorn-barnacle in hanging from a long mus- 102 ANIMAL LIFE IN THE SEA AND ON THE LAND. cular stalk. The shell opens at the side, but the arrange- ment of the animal is the same as in the acorn-barnacle. It also has twelve pairs of jointed and ciliated limbs, which it throws out at regular intervals. 11. In former times these same goose -barnacles were thought to change into birds. There is a certain goose frequenting the western coasts of the British Isles, called the barnacle- goose, which was thought, even by learned men, to have sprung from the barnacle. The follow- ing quaint description of the transformation was written in the sixteenth century : " When the shel gapeth open " we see " the legs of the bird hanging out," then the bird, increasing in size, " hangeth only by the bill," and "in Fig 60< _ GoosE . short space after it cometh to full matu- barnacles. rity and falleth into the sea, where it gathereth feathers, and groweth to a fowl bigger than a mallard, and lesser than a goose." People believed that this change was actually going on before them, and there was some difficulty in proving it to be only a fable. SPIDERS. 103 XVII. SPIDERS. SUB-KINGDOM, ARTHROPOD A : CLASS, ARACHNIDA. 1. Spiders. — Although spiders are shunned and despised, they are mostly harmless creatures, quietly pursuing their work of destroying insects. They have a singular fancy for resting with their heads downward, and instead of liv- ing in pairs, they prefer to live alone. The females are usually larger than the males, and they show no good feeling towards their mates, eating them if they have an opportunity. In some cases, however, they live peacea- bly together for a time. 2. Examination of a Spider. — The two divisions of the spider's body are easily seen. The cephalo-thorax has a horny covering, but the abdomen is soft. It is entirely without limbs, and is united to the cephalo- thorax by a short stalk. Spiders have four pairs of 1 egs, ending in hooks, which may be seen in Fig. 61. Near the mouth are hooked man- dibles, which contain a slit for throwing out a poisonous fluid to kill their prey. They have from six to eight eyes, which are grouped together on the top of the head. Fiu;. 61. — Foot of Spider, magnified. 104 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fig. 62. — Geometric Web op Garden- spider. The more highly developed spi- ders have a heart and blood- vessels. They breathe by air-sacs and tubes, which open on the under surface of the abdomen. The nervous ganglia of the head and thorax are united into a mass slightly resembling a brain. 3. Spinning Silk.— Spiders are provided with SPIDERS. 105 a curious set of machinery for spinning their webs. At the end of the abdomen are three pairs of "spinnerets," the last pair often extending behind the body like two prongs (Fig. 63). On examining these spinnerets we shall find them covered with tiny points ; from each of these flows a stream of gum- my fluid, which hardens into silk when it reaches the air. The movable spinnerets are under the control of the spider, and when they are held close together the fine Fl S- 63 - — gplN - ... . . NERETS OF SPI- streams issuing from them unite into one DER . thread before hardening, but if the spinner- ets are held apart the threads harden separately. By pressing the spinnerets against any object the fluid silk is forced out of the tubes and adheres to its surface, conse- quently it is drawn out when the spinnerets are lifted. The hind-legs are also used in helping to draw the delicate stream of silk, and guiding it to form various designs. 4. In this way a spider's web which we can barely see may be composed of more than a thousand threads. Like a piece of ordinary rope, it is stronger for being made up of small cords, but notwithstanding this the silk is too delicate to be of service to man, and all attempts to weave it into cloth have failed. 5. Uses of the Web. — Some spiders use their webs as traps to catch their prey, and those that live in holes or under- neath stones generally line their hiding-places with web. Nearly all spiders enclose their eggs in a silken cocoon, which, in some species, the mother carries on her back. The young spiders remain in the web until they have grown to a considerable size, when the mother sometimes tears open the web, and the baby spiders may be seen swarm- ing over her, as in Fig. 64. When the time arrives to 5* 106 ANIMAL LIFE IN THE SEA AND ON THE LAND. wean them from her back the mother shakes or kicks them off with her feet, and they scamper away to begin life by themselves. Two thousand young spiders have been found in one cocoon. Fi<;. 64. — Female Spider with Young Ones. 6. Feeding the Little Ones. — When feeding her babies, the mother holds a nice plump fly, or some such dainty morsel, while the little ones gather round and suck its juices. When their hunger is satisfied they run off, and a new set comes to the feast. The mother often kills some of her own little ones to feed the remaining spiders of her numerous brood. 7. Cobwebs. — What could be more charming than the filmy cobwebs that ornament the country road-sides, the fences, and the bushes in the early mornings of summer, every thread bearing a precious load of dew-drops ? Al- though the webs remain through the day, they please us most when sparkling with dew. Those flat w r ebs that are so familiar to us all slope down into a cunning little tube w 7 hich leads off among the grass. If you look closely you will find the spider hiding just inside this tube, and watch- SPIDERS. 107 ing intently for some insect to alight on its snare. When this happy event occurs, the spider runs out, and seizing its prey, carries it into the tube, where it sucks the juices of its victim and casts away the dead body. 8. Garden-spider. — Our common black and yellow gar- den-spider weaves a wheel-shaped web like that which is shown in the picture on page 104. This web is really a work of art. First, the framework for the wheel is made by a number of threads crossing each other at one point, and firmly attached at both ends to surrounding objects. These threads are like the spokes of a wheel, and upon them the spider fastens a spiral thread, making circle after circle. 9. The spider then stations itself, head downward, at the centre of the web, from which point it can feel the slightest motion made by an insect alighting upon it, and can quick- ly reach the spot, to secure its victim by additional threads. This garden - spider places her eggs in a pear-shaped co- coon, which you will see represented in the picture. 10. Gossamer-spiders. — Some small spiders have a fan- tastic habit of weaving balloons for themselves and sail- ing through the air. They pass by the general name of " gossamer-spiders." Placing themselves in some high po- sition, such as the tops of fences, with their heads towards the wind, and their spinnerets open, they allow a stream of fluid silk to be blown out by the current. The spider then makes a spring, and, grasping the thread with its feet, is carried by the wind for long distances, completely surrounded by a mass of its own web. These little fairy balloons may be seen floating through the air almost any fine day in the autumn. 11. Water-spider. — : Besides those that mount into the air, there are some spiders that live in the water. The 108 ANIMAL LIFE IN THE SEA AND ON THE LAND. mrnsm curious water-spi- der makes a bell-shaped cocoon of silk under the water, and fastens it to the leaves and twigs of growing plants. As the spider is an air-breathing animal, its young ones must have a supply of air, and the patient mother dis- plays the greatest ingenuity in obtaining it. She floats upon the surface of the water until in some way a bubble of air forms upon her abdomen; this she holds either by her hind-legs or by the long hairs on her body, and sinking rapidly un- derneath her cocoon, lets go of the bubble, which of course rises into the little bell. In this way bubble after bubble is stored away until the bell is filled with air. 12. Tarantula. — The tarantula, or trap-door spider, lives in warm countries, and digs for its nest a hole in the ground two inches or more in depth. The hole is neatly Fig. 65 — Nest of Ta- rantula. SPIDERS. 109 lined with real raw silk, and tightly covered with a most ingenious lid. How do you suppose the spider manages to make this circular lid of the exact size, and then fasten it on with a silken hinge? The top of the nest is first covered with a web of the proper shape, on which is placed a small quantity of earth; over this is spread an- other web, then more clay, so that the lid is composed of layer after layer of web and fine clay, which harden into a thin, stiff mass. The webs on one side are attached to the edge of the nest to form the hinge. 13. If the lid is closed it looks so exactly like the sur- rounding soil that these nests are not easily found. The concealment is completed by a cunning habit of cover- ing the door with moss, or some substance similar to that which grows around it. When in its nest the spider holds on to the door so tightly by its mandibles and fore-feet that the lid cannot be raised from the outside. 110 ANIMAL LIFE IN THE SEA AND ON THE LAND. XVIII. INSECTS. SUB-KINGDOM, ARTHROPOD A : CLASS, INSECTA. 1. Largest Class in the Animal Kingdom. — Insects them- selves are mostly small, but the class to which they belong is the largest class in the animal king- dom, and contains more than two hundred thousand species. 2. Found in ev- ery Part of the World.— These lit- tle creatures are found in all the countries and oce- anic islands that man has reached; they inhabit hot springs as well as the coldest streams. Hum- boldt found them on the Andes far above the line of perpetual snow, and Darwin, on the early voyage of the Beagle, found a dragon-fly two hundred and fifty miles from land. — Diagram op an Insect. B, C, D, segments of the thorax ; E, ab- domen ; F, ovipositor. INSECTS. Ill 3. Body made up of Segments with no Skeleton. — Insects have no internal skeleton, but they are covered with a horny skin. The head, thorax, and abdomen are entirely distinct, and each part is mostly divided into segments such as are represented in the diagram (Fig. 66). 4. Compound Eyes. — Conspicuous upon the sides of the head are the large round eyes, which, examined through a microscope, will be found covered with numerous flat surfaces or lenses (Fig. 67). These are called compound eyes, for they consist of a great number of eyes crowded into one mass ; and they have the power of looking in many direc- tions at the same time. In addition to their compound eyes, most insects have three simple eyes placed between them. The antenna?, or feelers, are % F ' ^ OWING gq M _ also interesting, and vou will find pound Eyes, Simple ., . , Eyes, and Antennae. great variety in their shapes. 5. Limbs of Insects. — To the thorax are attached three pairs of legs, and mostly two pairs of wings. These wings are thin and delicate, and are very large in proportion to the body. They are supported by a net-work of hollow tubes which enclose air-pipes and blood-vessels side by side. 6. The abdomen has no limbs, and it often ends in a piercer or sting, which is called the " ovipositor." You may have noticed in larger insects a curious sliding in and out of the segments of the abdomen. This bellows-like action helps to change the air in the air-tubes. V. Organs of Digestion and Circulation. — The (Esophagus leads into a crop from which the food enters the gizzard, where it is crushed and passed on to the true stomach 112 ANIMAL LIFE IN THE SEA AND ON THE LAND. (Fig. 68). Insects have no distinct heart, and the blood is propelled by the contraction of eight sacs, which al- low it to flow only towards the head. The blood is colorless, and fills the irregular spaces left between the or- gans. 8. Breathing Apparatus. — Insects breathe by tracheae, which are air- tubes passing through every part of the body. Being filled with air, the tracheae supply the blood abundantly with oxygen, and at the same time di- minish the weight of the body. These tubes are composed of elastic threads wound in a close spiral (Fig. 69), giving them great strength and light- ness, and preventing the possibility of their being pressed together and closed. The tracheae open on the surface of the body in small holes, called " stigmata," which are arranged on the sides of the thorax and abdomen, and are so contrived as to admit air freely, while they exclude water or dust. A drop of oil on the abdomen of an insect will kill it by closing the stigmata and causing suffocation. 9. Insects have no Voices. — No insect is known to have a voice. The various noises of insects, so commonly heard, are caused by the rapid vibration of their wings, or by rubbing together some hard parts of their bodies. 10. Metamorphosis.— Most young insects Fig. 68. — Alimentary Canal of a Beetle. b, oesophagus ; c, crop ; d, gizzard; e, stom- ach ; g, iu(;estiue. Fig. 69. — Tra- cheae of an In- sect, showing Elastic Spiral Thread. INSECTS. 113 are very different from their parents, and before reaching their perfect state they pass through a succession of changes called "metamorphosis." As butterflies are fa- miliar insects, let us take them for an example, and study the changes through which they pass. Butterfly in the Larva, Pupa, and Imago State. 11. The Larva of a Butterfly. — From the eggs of but- terflies are hatched young caterpillars. The caterpillar crawls over the plant upon which it was born, eagerly de- vouring the green leaves, as its mouth is fitted for chew- ing. It grows rapidly, and sheds its coat several times. During this period of its existence it is called a " larva." 12. The Pupa or Chrysalis State. — At length the larva leaves off eating, and enters the "pupa" or "chrysalis" state. Wrapped in a dry skin, and hanging head down- ward suspended by a silken thread, it remains for a time apparently dead. Shut up, however, in the silence of this 114 ANIMAL LIFE IN THE SEA AND ON THE LAND. temporary prison, a marvellous change is going on, and when the skin bursts a full-grown butterfly appears, fur- nished with wings and arrayed in bright colors. These three stages are represented in Fig. 10. The attractive insect now in no way reminds us of the caterpillar from which it sprang. 13. The Imago or Perfect Butterfly. — When the but- terfly first leaves the case its wings are crumpled and moist, and before attempting to fly it rests a while, until the wings stretch out to their full size. The delicate hues of the butterflies are due to the small feather - like scales with which they are covered. The scales overlap each other, as shown in Fig. 71. 14. Great changes have also taken place Fig. vi.—Scales on the Wing of a Moth, in the mouth, and henceforth a butter- fly sucks the sweet juices of flowers through a slender tube, which, when not in use, may be rolled up spirally under the head. Our beautiful insect has now reached the " imago " or perfect state, and the great aim of this part of its existence is to choose a mate. In this it makes no mistakes. The image of its own kind seems to be im- pressed upon its fancy, so that it never mates with any but its own species. Insects know each other when they meet, just as they know the right flowers to feed upon, and in the same way the female butterfly selects the INSECTS. 115 proper spot for her eggs, generally plac- ing them on some plant whose leaves are suitable food for |jj her caterpillar chil- dren. 15. Nearly all insects pass p: v through these three condi- IpF I \ tions, the larva, the pupa, and the imago, as we have before stated. Their larvae are known by the various names of caterpillars, grubs, and maggots. By keeping 116 ANIMAL LIFE IN THE SEA AND ON THE LAND. a few caterpillars you may watch for yourselves all these interesting changes. 16. What could possibly seem more aimless than the joyous, careless flitting of a butterfly! Floating hither and thither through the bright sunshine, and folding together its elegant wings above the choicest flowers, its life ap- pears a most luxurious one; still it has its own part to play. IV. Flowers fertilized by Insects.— It is a well-known fact that most bright-colored flowers are dependent upon the visits of insects (especially of bees) to perfect their seeds, and thus to keep up a succession of new plants from one year to another. The insects are attracted by the showy petals, and they enter the flowers to obtain the honey wdiich is stored up in the bottom of the tube. In so doing, grains of pollen adhere to their heads and wings, and are carried from one flower to another. These pollen grains lodge upon the moist surface of the pistils as the insects brush past them, and in due time seeds are pro- duced. 18. Bright-colored Insects attracted by bright Flowers. — Butterflies are great rovers. Having no homes of their own, they flit gayly about and visit the most brilliant blossoms. Throughout nature we find highly colored birds and insects have the same preference for bright flowers and fruits as is shown by the butterflies. 1 9. Butterflies and Moths contrasted. — Many of our moths resemble butterflies ; and as both of these insects change from caterpillars, it will be well to notice some of the differences between them. In the first place, true butter- flies fly only in the daytime. Their antennae are long and thread - like, with knobs at the end. When at rest, the wings are generally folded together and held erect above INSECTS. 117 the body, thus concealing the more brightly colored upper surfaces, and affording the insect protection against its enemies. The under side of the wings often resembles in color the flower upon which the butterfly feeds. Fio;. *73. — Moth and Larwe. 20. Moths fly only at night or during twilight. The body is generally stouter and more robust than that of the butterfly. Their antenna? are tapering, and sometimes beautifully feathered (Fig. 73). They do not fold their wings in repose, and their larvae enclose themselves in silken cocoons. 21. Silk-worms. — Silk-worms, the most useful of these 118 ANIMAL LIFE IN THE SEA AND ON THE LAND. insects, are extensively cultivated for the silk of their co- coons. When the pupae are ready to leave the cocoon they make a hole through it for their escape, which breaks the thread of silk. To prevent this it is custom- ary, when silk -worms are raised for profit, to kill the pupae by submitting their cocoons to a great heat. The cocoons are afterwards soaked in warm water to soften a gummy substance which they contain, and the silk can then be wound off in an unbroken thread. The length of a thread of silk has been estimated to be nine hundred feet. 22. In commencing its cocoon the larva attaches the silk to some fixed object, then winds itself in its own web, thickening the cocoon upon the inside. The moths of the silk-worm have grown so helpless from confinement that the female is nearly as motionless as if she had no wings, and the male merely flutters around his companion with- out leaving the ground. It has been found that after three generations raised in the open air they recover their lost power of flight. BEES. 119 XIX. BEES. SUB-KDsGDOM, ARTHROPODA : CLASS, ENSECTA. 1. Transparent Wings Hooked. — You may have noticed how thin and transparent the wings of bees are, and that they are supported by delicate veins. Look at them now with your microscopes, and you will see small hooks on the edge (Fig. 74), which fasten together the front and back wing during flight, in or- der that thev may move as Fisr. 74. -Wings of a Bee, showing the Hooks. one wing. 2. The Sting.— The sting of the female (Fig. 75) is a remarkable instrument at the end of the abdomen. It consists of two darts, a, and a sheath, b, connected with a poison -gland, e. The wound is first made with the sheath, after which the darts are thrust out to deepen it. These darts have a number of pointed barbs at the end, d, and it is difficult to remove them from the wound, so they sometimes break off. This loss of the sting causes the bee to die, though not always immediately. The sting, or ovipositor, varies in form with different kinds of bees, and it is sometimes used for cut- ting, boring, and sawing holes in which to deposit the eggs. Male bees have no sting, and are therefore harmless. 120 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fig. 75.— A Bef/s Sting. d, dart magnified. tinued several inches down the trunk, parallel to the grain of the wood. This tun- nel is afterwards divided into cells, in each of which is placed an egg with a supply of food for the young lar- va. The parti- tions between the cells are made of the sawdust which has collected from her boring, moist- ened with a gum- my fluid which the bee secretes. She 3. Social Bees and Solitary Bees. — Humble - bees and hive - bees live in large families, and are called social bees. There are also solitary bees which live entirely alone. 4. The Carpenter-bee. — The carpen- ter-bee is an interesting example of a solitary bee. She bores her nest in old wood, mostly selecting the dead limb of a tree, an old post, or wooden railing. One of these nests is shown in Fig. 76. The bee bores a tube which soon makes a sudden turn, and is con- Fig. 76. — Nest of Carpenter-bee. BEES. 121 seems to know that the egg first deposited at the bottom of the tube will hatch first, so she bores a second opening at that part of the tunnel, through which the young bees come forth in succession at the proper time. 5. Humble-bees. — Humble-bees, as we have said, are among the social bees. They make their nests in holes in the ground (Fig. 77), often taking pos- session of a deserted mouse nest. All the colony, except the fe- males, die when win- ter comes. These fe- males remain in a tor- pid state, concealed among moss or rotten wood, to start new colonies the following spring. 6. Hive -bees. — The habits of hive-bees are exceedingly curious, and deserve our espe- cial study. Every hive contains a queen-bee, workers, and drones (Fig. 78). 7. The Workers Build the Nests. — The whole labor of building the nest and providing for the large fam- ily falls upon the workers. They have a softer material to work in than the carpenter-bee, since their nest is built of wax, which is a secretion of their bodies, and which (5 Nest of Hcmble-bee. 122 ANIMAL LIFE IN THE SEA AND ON THE LAND. forms in scales between the segments of the abdomen. With their feet the bees remove the wax, and work it with Fig. 78. — Hive-bees, i, queen ; b, worker j c, drone. their mouths and mandibles, mixing it with saliva until it becomes soft and white. 8. It is then placed upon the ceiling of the hive, and the cells are carefully shaped and fitted to each other, forming the honey-comb which is our wonder and admira- tion. The manner in which the six-sided cells fit together gives the greatest possible amount of space, while it re- quires the least material for building. 9. Gathering Honey. — In collecting honey for the hive a bee goes steadily from one blossom to another, visiting flowers of only one kind on each excursion; thus it does not mix the honey from different flowers. The long tongue, or proboscis, enters the tube of the flower and laps up the honey. The tube of some flowers is too long and narrow for the bee to enter, so the honey is sucked BEES. 123 from the cup on the outside of the flower, or the tube is pierced by proboscis. 10. Most of this honey re- mains in the crop, or honey-sac, until the bee returns to the hive. By the contraction of certain muscles the honey is forced back again through the mouth, and is poured into the cell. As the cells become full, they are sealed up tightly with wax. The hon- ey has undergone some change while within the body of the bee, for it is quite different from the pure juice taken from the flowers. 11. Pollen Baskets.— When bees leave the flowers the hair on their bodies and legs is cov- ered with pollen, which they Fig. 79 -Little Plunderers. 124 ANIMAL LIFE IN THE SEA AND ON THE LAND. brush back into little pockets on their hind-legs and carry- to the hive. It is a singular fact that the queen and the drones have no such pollen baskets. As they never go out to gather honey, they need none. 12. The Queen-bee. — Each hive has one queen, and she is the only perfectly developed female. She lays all the eggs, which sometimes amount to two thousand in a sin- gle day. Different sized cells have been prepared for the three classes of bees, and the queen deposits each egg in its proper cell, gluing it slightly to the bottom. She first lays eggs which are to produce the workers, afterwards those which produce drones, the last being placed in larger cells. 13. Duties of the Nurses. — In three or four days the eggs hatch into little white grubs, and then the duties of the nurses, or workers, begin. The nurses feed the larvae with a mixture of pollen and honey, which they have first swallowed, and which is already partly digested. The larva? require a great quantity of food, and grow rapidly until they almost fill the cell. When they refuse to eat any longer, the nurses seal over the cells until the young bees are perfectly developed. 14. The Perfect Bee. — Fastened within its cell, the larva spins for itself a silken cocoon, and remains inactive, eat- ing no food while the wonderful change is taking place. The care of the nurses has ceased, and when the perfect bee is ready to leave the cell it struggles out alone, and enters the busy throng outside with no one to welcome it. The workers soon take possession of the empty cell, and prepare it for future occupants. 15. Treatment of a Young Queen. — On the other hand, the young queen in her cell is treated with the greatest distinction. The larva is given richer food and in larger BEES. 125 quantities than the workers or drones receive. When she is ready to leave the cell, the workers gather around and gnaw at the top of the cell until it is so thin that the movements of the young queen within may be watched. A hole is made in this cover large enough for her to extend her proboscis, and she is fed in this position for several days, uttering the while a peculiar cry called piping. 16. The queen seems to have a hatred for those of her own sex, and she will destroy the young queens that come within her reach. Consequently, if the bees have not yet swarmed, the workers do not allow a young queen to stir from her cell. After the old queen has left the hive with her swarm, the young queens are liberated at intervals of a few days, and they lose no opportunity to kill each other. 1 7. The Larva of a Worker may develop into a Queen. — If by any accident the hive is left without a queen, the bees are thrown into great excitement, but they soon wak- en up to the necessity for action, and they begin, as it were, to cultivate a queen. They select three adjoining worker cells which contain larvae, and cutting away the partition walls, convert them into one large cell. Two of the larvae are destroyed, and the remaining one, by being fed on royal food, and having plenty of room and other favorable conditions, grows into a queen instead of a worker. This slight change of treatment not only gives her a different form and color, but it alters her whole nat- ure, and gives her different instincts. 18. So you will see that queen-bees and workers come from the same kind of larvae, and that these larvae de- velop, according to the circumstances under which they are placed, either into queens or into workers. 19. Drones killed by the Workers. — The drones are 126 ANIMAL LIFE IN THE SEA AND ON THE LAND. males, and they take no part in the work of the hive. In the latter part of summer the workers kill them without mercy, as if they were determined to support them no longer. They attack the drones, and sting them between the rings of the abdomen, afterwards throwing them out of the hive. 20. Swarming. — Bees usually swarm, or fly off in search of a new home, in the spring, never leaving the hive, how- ever, until it is well stocked with eggs and the weather is warm. When about to swarm, the queen and the workers become very much agitated, hurrying to and fro for several days before they start. As the time for de- parture arrives, several bees fly in circles around the hive ; suddenly the noise and bustle are hushed, and they all enter within. At a given signal, those which are to com- pose the swarm fly off rapidly, and select some tree or bush on which to alight. If their queen is not with them, they soon discover the mistake and return to the hive, where they wait for several days before a second attempt is made. 21. When the bees have entered their new home, they arrange themselves in a loop, or festoon, by hooking their claws together, and in this manner they hang from the roof of the hive. Thus they continue motionless for some time, while a store of wax is forming with which to build their new comb. 22. The bees which remain in the old hive after the swarm has left quietly pursue their labors, and a new brood soon fills the vacancies. The young queens, in their turn, lead off new swarms, and thus proceeds the busy life in a beehive. There are sometimes as many as fifty thousand bees in one hive, yet the work goes on without the slightest disorder or confusion. BEES. 127 23. Ventilating the Hive. — The workers keep the hive perfectly clean, and allow no dead bees or other impurities to remain within it. They are also careful that it shall be well ventilated. To accomplish this a certain number of bees continually fan their wings as if flying, although their feet are fastened to the floor. Some bees are occa- sionally stationed outside the hive to perform the same movements, but the greater number are within, one set relieving another after a certain time. The rapid motion of their wings causes a current of fresh air to pass through the hive; it also produces the humming sound which is constantly heard from a hive of bees. 128 ANIMAL LIFE IN THE SEA AND ON THE LAND. XX. WASPS AND MOSQUITOES. SUB-KINGDOM, ARTHROPODA : CLASS, INSECTA. 1. Wasps. — Wasps have a general resemblance to bees, although they may be distinguished by their wings, which, when at rest, are laid over the body ; also by the deep stalk-like division between the thorax and abdomen. Wasps differ great- ly in their habits. Like the bees, some live alone, others live in colonies. 2. The Mud-wasp. — Our common mud-wasp is among the solitary ones. This wasp makes its nest of mud, fastened to the side of a wall or under a ceiling. The nest consists of long cells arranged hor- izontally. In each cell is deposited one egg and a supply of little spiders for the young larva to feed upon after it is hatched. The Fig. 80. — Digger-wasp — Cocoon and Larva. WASPS AND MOSQUITOES. 129 Fig. 81. — Nest of Mud-wasp. spiders are not killed, but only stunned, and imprisoned alive when the end of the cell is fastened up. 3. In Fig. 81 you see a cell which has not yet been closed. The remaining cells were full of little green spi- ders,, still active, when this nest was found. 4. Social Wasps. — Social wasps live in large families, which contain females, work- ers, and males. When win- ter approaches, all the wasps die except the females; these creep into some safe place, and sleep through the cold weather with their wings and legs tightly folded. In the spring they revive, and each female starts a new nest for herself. 5. Nests built of Paper. — The nests of social wasps are always built of paper. Indeed, wasps were the first paper- makers. Long before man had learned the various proc- esses required for manufacturing it, wasps had mastered the secret. Their paper is beautifully variegated, and be- ing made of the fibres of wood, it is so durable as to bear exposure to rains and storms. Gnawing these fibres from some old fence or tree-trunk, the wasps moisten them with saliva until by the action of their jaws a paste is formed ready to spread out in a thin sheet. In looking at a piece of this paper, the wavy stripes will show just how far each bundle of fibre went towards forming the nest. 6. Starting the Colony. — As we have stated, there is but one wasp to do all the work in starting the home, so the building goes on slowly at first. By the time three or 6* 130 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fig. 82. — Nksts of Social Wasps. four cells are fin- ished the young workers which occupied them are ready to help the mother, who has been busy building the nest, de- positing eggs, and feeding the hungry larvae. Other cells are made and more eggs deposited, the work going on rapidly. The first wasps hatched are the workers; the perfect males and females do not appear until nearly the end of the season. WASPS AND MOSQUITOES. 131 7. Some kinds of wasps make their nests in holes in the ground, others fasten them to walls or to the branches of trees. The flat nests in Fig. 82 are built without any covering to the cells. 8. The Hornet's Nest. — A much more elaborate nest is made by the hornet. The one represented in Fig. 83 is 83. — Hornets' Nest. cut open at one side to show the interior. It is formed of tiers of cells, one above another, with their mouths open- ing downward ; the tiers are attached to little stalks which hang from the top of the nest. The whole is cov- 132 ANIMAL LIFE IN THE SEA AND ON THE LAND. ered with several envelopes of paper, and the entrance is through a circular opening in the bottom. When it be- comes necessary to enlarge the nest, new envelopes are added on the outside, and the inner covers are removed to make room for more cells. These nests are found in the woods, attached to the branches of trees. 9. The Yellow-jacket. — The yellow - jacket is a small black wasp marked with bands and spots of yellow. Its nest is much like that of a hornet, but smaller and more pointed, with the entrance on one side, near the bottom. The yellow - jacket sometimes attacks persons without provocation, and its sting is very severe. As a general thing, wasps do not sting unless they are irritated, but they are zealous in guarding their nests, and become agi- tated upon any approach to it ; if it is molested in any way, they rush upon the intruder without mercy. 10. The Mosquito. — Now let us glance at the mosquito. Its sting is on the head, and consists of several sharp lances and sucking tubes enclosed in a flexible sheath. After lancing the flesh, mosquitoes let fall a drop of poi^ son, which makes the blood so thin that they can readily suck it through their tubes. 1 1 . Young Mosquitoes in the Water. — Mosquitoes lay their eggs in water. Their larvae pass by the name of " wigglers," and they may be seen in any stagnant pool. Here they remain during winter, when the ponds are covered with ice, and the mosquitoes of last season have been killed off with the cold. So, while we are enjoying a rest from the attentions of these little pests, another generation is coming on for next season. 12. The larvae move through the water by sudden jerks. Their breathing organs are towards the tail, so they swim with the head down, as may be seen at E in Fig. 84, but WASPS AND MOSQUITOES. 133 after they throw off the first skin and enter the pupa state, they breathe through the thorax, and keep the head at the surface of the water. Once more the skin splits, and they fly away full-grown mosquitoes. The dry case of the pupa forms a sort of boat, upon which the insect may rest and spread its wings before taking flight. 13. Yon may see this interesting metamorphosis going on in any pond in summer-time. A bright sunny morning brings thousands of these little boats to the surface, and you may be so fortunate as to see the occupant burst its shell and fly off into the sunlight. Fig. 84. — Different Stages in the Growth of a Mosquito. A. boat of eggs ; B, eggs highly magnified ; d, with lid open for the escape of the larva: C, D, pnpse; K, larva "magnified, showing respiratory tubes (e), aual tins (/), antennae {g); F, imago. 14. The Eggs. — The eggs of mosquitoes are cemented together side by side, and protected by some water-proof covering which enables them to float securely upon the 134 ANIMAL LIFE IN THE SEA AND ON THE LAND. water, like miniature life -boats, which they really are. Each egg, moreover, contains a tiny air-bubble, and if the little life-boat should happen to be plunged beneath the surface, it rises quickly, and always with the right side up. These rafts of eggs are shown nicely at A, in Fig. 84. At B you will see the eggs magnified, with a -curious lid at d, for the escape of the larva. 15. House-flies. — Our common house-flies live with us on intimate terms, and take great liberties in our homes; still, the early part of their lives is concealed from us, and we scarcely think about how they come or where they go. 16. Most flies perish when cold weather comes, but a few of the strong, healthy females creep into some crevice or corner, where they lie in a torpid state until the next summer. Here the eggs are deposited from which a new generation springs. In hot climates, and in rooms which are kept constantly warm, flies remain active all the year. ANTS. 135 XXI. ANTS. SUB-KINGDOM, ARTHROPODA : CLASS, INSECTA. 1. Remarkable Instinct of Ants. — Ants are considered the most highly developed of all insects. Indeed, none of the lower animals possess such remarkable instincts as the ants. They show great wisdom and ingenuity in building their nests and in reaching any desired point. They make roads for themselves by carefully removing any obstacle in their way. They also dig tunnels of con- siderable length, sometimes resorting to this method for crossing broad rivers. They protect their nests, fight bat- tles, gather food, tend their young, take care of domestic animals, and possess slaves. Their industry is not ex- celled by the bees and wasps. They work all day, and, when there is necessity, even at night. 2. Their one Flight into the Air. — Ants live in families, consisting of males, females, and workers. At first the young males and females are furnished with wings, and they fly from the nest to select their mates. Immediate- ly after this first and only flight the males die, and the females strip off their wings, and do not leave the nest again. 3. Labor of the Workers. — The workers are much more numerous than the other classes; some of them serve as soldiers, others, which are generally smaller, serve as 136 ANIMAL LIFE IN THE SEA AND ON THE LAND. nurses. All the labor of the colony falls upon the work- ers, and they attend to their various duties in the most orderly manner. 4. Ants' Nests. — Ants do not all build their nests in the same way. Some species heap up a mass of small sticks and pine leaves; some bore into the trunks of old Fig. 85. — Ant Nest, with Underground Passages. trees ; but most ants make holes in the ground, with a little mound of earth around the entrance, which we call an ant-hill. These nests are carefully contrived, with passages and avenues leading to many chambers, as you will see in Fig. 85. The entrances are closed every night, and opened in the morning. If it rains during the day they remain closed, and the ants are confined within the nest. ANTS. 137 5. Nurses' Care of the Eggs and Grubs. — The eggs, which are scarcely large enough to be visible, are not deposited in any especial place by the females, but are immediately taken possession of by the nurses, who carry them to some favorable place, and who are henceforth devoted in their attentions to them, constantly licking and cleaning them, and frequently changing their position. 6. From the eggs are hatched little white grubs, which are entirely dependent upon their nurses for food. Every morning they are carried into the sunshine, or at least to the upper chambers that have been warmed by the sun, and towards evening they are again taken back to the bottom of the nest, where there is no chilliness. Imagine the labor — each one of those thousands of larva car- ried separately in the mouth of a faithful nurse ! If a shower comes on, or if the young family is threatened with danger, they are quickly taken to some safe place. 7. When ready to enter the pupa state, the larvae cover themselves with a sort of web (Fig. 86), and are still carried back and forth by the nurses, who con- tinually clean them. Sir John Lubbock, in his recent work on ants, states that when the pupa are ready to leave their cases the nurses help them to escape. " It is very pretty," he says, " to see the older ants helping them to extricate themselves, carefully unfolding their legs and smoothing out the wings with truly feminine tenderness and delicacy." Larva, Cocoon, and Pcp^e of Red Ant (magnified). 138 ANIMAL LIFE IN THE SEA AND ON THE LAND. 8. Cleanliness. — Ants not only keep their homes neat, but they are careful of their own personal cleanliness. Their little feet are covered with hairs, which form good brushes, and no particles of dust are allowed to remain on their bodies. They may often be seen rubbing their feet togeth- er to clean them, as flies do. The antennae of ants (Fig. SI) are bent like an elbow, and with them the act- ive little creatures examine every ob- ject they meet. 9. Recognizing Members of their own Family. — If we notice ants in their travels, we shall see two dis- tinct lines, one moving towards the nest, the other leaving it. Those that are returning without a load stop, and, with their antennae, salute their sisters carrying burdens, and this they do so quickly as not to break or interrupt the line. 10. In one nest there may, perhaps, be four hundred thousand ants. Notwithstanding these immense numbers, ANTS. 139 a stranger upon entering the nest is immediately attacked, which fact shows that the ants in the community have some power of recognizing each other. They even know members of their own family after a long absence, and welcome them back to their old home. 11. If an ant has discovered a good feeding-ground, it seems to spread the news to its fellows, and often returns with a troop of them to share the feast. 12. Favorite Places for their Nests. — You have probably noticed the little ants that burrow under the pavements in our streets and door-yards, and have wondered why they choose situations so exposed that many of them are trodden underfoot, while their little hillocks of earth are swept away by the broom. 13. We may rest assured that they have good reasons for this singular choice, and that the situations are not undesirable, or the ants would not seek them. 14. In the first place, the ants must have a care to supply their growing family with food, and where could they fare better than near the homes of man ? The tiny crumbs dropped by the children are treasures to the eco- nomical ants, whose sharp eyes see many chances for feast- ing upon things we have thrown aside as useless. 15. Then, too, the bed of fine gravel which the brick- layer smooths so carefully to lay his bricks on is a fine place for the ants to burrow in. The sun, shining upon the bricks, heats them, and also the earth beneath, and makes a warm place for the ants to put their larvae when they bring them up out of their nests. 16. You know how common it is, on turning over large stones, to find the ground beneath covered with the white larvae of ants, which are quickly carried away and hidden. The stones become heated during the day, and retain the 140 ANIMAL LIFE IN THE SEA AND ON THE LAND. heat long after the sun has set. Ants, no doubt, select these spots that they may secure a safe, warm place in which to hasten the development of their larvae and pupae. 1 7. Singular Relations with Plant-lice. — Ants feed chief- ly upon insects, killing great numbers of them, and they also eat honey, fruit, and almost any sweet substance. This liking for sweets has led them to form singular re- lations with our common green plant -lice, the aphides. The plant-lice secrete a sweet liquid called honey-dew, of which ants are very fond, and which they obtain by tap- ping the lice with their antennae. 18. Some species of ants ascend into bushes in search of these lice, and, having found them, watch over and de- fend them from attacks by other insects. Sir John Lub- bock says that the ants take care of the brown eggs of aphides during winter, carrying them to the lower cham- bers of the nest when it is disturbed. In the spring, when the young aphides hatch, they are brought out and placed on tender shoots of plants. 19. This is a remarkable instance of forethought. The ants derive no immediate benefit from the eggs, yet by taking care of them they secure a supply of their favorite honey-dew for the following summer. 20. Capturing Slaves. — Fierce battles are fought between different colonies of ants apparently for the sole purpose of capturing slaves. This instinct is so strong with the common red-ant that it is spoken of as the " slave-mak- ing ant." It frequently invades the nests of black-ants, and fearful struggles occur between the two colonies. 21. When about to attack the enemy, red-ants leave the nest in full force and march directly to the battle-field. It is not a general warfare, but each red-ant seizes upon some black one, and makes a desperate effort to kill it. ANTS. 141 After the battle, if the red-ants are victorious, they enter the conquered nest and cany off the larvae and pupse, which they bring up as slaves. These young slaves enter at once upon a life of toil, and make no effort to escape. 22. Degrad- ing Effects of Slavery.— It has been noticed that this sys- tem of slavery has a degrad- ing tendency among ants, as it is well known to have among men. Some of the slave-mak- ing ants are so accustomed to being waited upon that they have lost the art of building and of caring for their young, and are entire- ly dependent upon their slaves for these services. They have even lost the habit of feeding them- selves, and, although surrounded by food, they will starve unless fed by others. 23. The Harvesting Ants. — The harvesting ants of Texas Fig. 88. — Queen of Slate- making Ants (magnified). 142 ANIMAL LIFE IN THE SEA AND ON THE LAND. clear a circular space, ten or fifteen feet in diameter, around the entrance to their nests. Within this space nothing is allowed to grow but " ant rice " — a species of grass, the seeds of which are carefully gathered by the ants. 24. The Driver-ants. — Many species of ants in hot coun- tries hunt in large packs. The driver-ants of Africa hunt in this way, and render valuable service in clearing away decaying animal matter that might otherwise cause dis- ease. The dread of visits from these ants compels the inhabitants to keep their dwellings comparatively clean. These hunting ants are said to be blind, and go out chiefly at night. 25. Termites. — Termites, or white-ants, as they are called, do not properly belong here, as they are not true ants. Still, we will study something about them. They abound in all tropical countries, living in large communities and committing serious ravages. They build structures above- ground, often five feet high, composed of earth worked and patted until it becomes nearly as hard as stone. There is no external opening in these hills, but the entrance is placed at some distance, and is reached by underground galleries. OYSTERS. 143 XXII. OYSTERS. SUB-KINGDOM, MOLLUSCA : CLASS, LAMELLIBRANCHIATA. 1. Mollusks: the Mantle. — Having taken this mere glance at the Articulates, we will begin our study of Mollusks. This division includes soft-bodied animals which are usual- ly provided with shells, and which pass by the general name of "shell-fishes." Their bodies are enclosed by a delicate membrane called a " mantle," whose office it is to secrete the shell. On opening an oyster we see this thin, glistening mantle lining the shell as well as covering the oyster. 2. The Shell adapted to its Surroundings. — The shell is useful in protecting the soft body of the mollusk, and its strength and thickness are generally in proportion to the dangers to which the animal is exposed. Those species inhabiting shallow places in the ocean near the shore, and hence exposed to the beating of the waves, have stronger shells than those living in deep water. Fresh- water mol- lusks, on the other hand, generally have delicate shells. 3. Another provision of nature for the safety of the help- less mollusks may be seen in their coloring. Those which spend most of their lives at rest near the same spot, as oysters and clams do, are of the same general color as their surroundings. On the contrary, those that move about, as pectens and gasteropods, are often tinted with rich and beautiful colors. Mi ANIMAL LIFE IN THE SEA AND ON THE LAND. 4. A Bivalve Shell. — When a shell consists of two sep- arate pieces or valves opening by a hinge, it is called a bivalve. 5. The Shell of an Oyster examined. — A careful exam- ination of one mollusk will help us to understand all the others ; therefore we will take an oyster as our type. If we cannot obtain a living oyster, let us at least have the shell, and examine it carefully. What is the first thing you see? Is it the thin layers of which the shell is com- posed ? Fig. 89. — Oyster in the Shell (with Mantle removed from the Upper Surface). A, muscle; B, mantle; C, gills; D, labial palpi; E, hinge; F, month; G, liver and stomach ; II, heart. 6. These layers are very interesting. You will soon sus- pect that they have been caused by the growth of the oyster. By looking on the outside of the shell you may see the lines of growth, and perhaps you can detect the shape of the oyster when it was very small. The delicate mantle (B) has deposited new layers of shelly matter upon OYSTERS. 145 the inside from time to time, each layer extending a little beyond the edge of the last, and increasing the size of the shell. 7. After an oyster has obtained its full growth the shell does not increase further in size, but it becomes thicker by the addition of one layer inside of another, so that the age of an oyster may be estimated by the thickness of its shell. This thickening is readily seen at the hinge (E), which seems to have grown in until it encroaches upon the space intended for the oyster. Yet you will see that at one time the hinge was at the very tip of the beak. 8. In a freshly opened oyster you will notice a tough brown band in the hinge ; this is the ligament which unites the two valves, but, strangely enough, it acts like a spring which is constantly tending to throw the shell open. Let us see what causes this. The elastic, horny fibres which form the ligament are placed endwise be- tween the valves; consequently, they are squeezed when the shell is closed, and they try to make room for them- selves. If the ligaments in the hinge push the shell open, how, then, do you suppose it can be closed ? 9. The purple spot on the inside of each valve shows where a muscle was attached which extends right through the body of the oyster (A), and holds the two valves together. You know the oysterman has to cut the oyster loose from the shell at this point with his knife, and this is the only place at which the oyster is attached to the shell. The muscle is the tough part of the oyster, and when it shortens itself the valves are drawn together. If the muscle lengthens, the valves fly open, as is the case when the oyster dies. Bivalves naturally stand open with a stream of water flowing over the gills, unless they are forcibly held together by the muscle. Fortunately for us, 146 ANIMAL LIFE IN THE SEA AND ON THE LAND. oysters live some time after being taken out of the water, but they keep their valves closed to retain their moisture. 10. The inside of the shell is further marked by the " pallial line," which shows where the edge of the mantle has rested. By lifting the fringed edge of the mantle four delicate gills (C, Fig. 89) may be seen extending part way round the edge of the oyster. The gills are covered with cilia, which by rapid motion produce a current of water towards the mouth, bringing to it particles of food and, as the current flows away again, it carries off the waste matter. 11. Food floated to the helpless Oyster. — The helpless oyster, fastened down to its bed, has no possible way of seeking food, and it is therefore entirely dependent upon these currents of water. Coming in this way, the food necessarily consists of very small plants and animals, which are abundant in the sea, especially in the quiet places where oj^sters flourish. Oysters live in shallow water attached to some fixed object by the lower valve, which is larger and deeper than the other ; in it the oyster lies as in a trough. 12. The Oyster examined. — The mouth is a mere slit at the smaller end of the oyster (F), near the hinge. It is covered by four thin lips or folds of membrane, called "labial palpi" (D). An oesophagus leads to the stomach, and the intestine passes through the large liver (G), which is of a brownish-green color, and occupies most of the soft part of the oyster. 13. Oysters have no true head. The heart (H) may easily be seen in a clear space near the muscle, and in a freshly opened specimen it will beat slowly and regularly. It consists of two sacs, one large and transparent, the other small and brownish. OYSTERS. 147 14. Large Number of Young Ones. — Spawning season oc- curs during the summer months, at which time the eggs floating in the fluid around the gills give to it a thick, creamy appearance. Oysters are not then in good con- dition for food. They produce an immense number of young ones. It is thought one oyster may yield a million in a season, and the whole number of young oysters thrown out from an ordinary oyster-bank is almost incal- culable. The eggs leave the parent shell in puffs of milky fluid, and are sometimes so thick as to make the water look clouded until they are scattered by the waves. 15. They settle for Life. — When the young ones are hatched they swim about for a time, then attach them- selves for life to some solid object. Unless they find a clean, hard surface to fasten to, the little things will prob- ably perish in the mud or be devoured by larger animals. A very large proportion of the young is destroyed in this way. 16. Oyster-beds. — Oyster-beds generally exist in brack- ish water upon a bottom of clay or mud which is firm enough to prevent the oysters from sinking into it. The water must also contain lime to supply the oyster with the material for its shell. It is found that oyster-beds increase in the direction of the current, the young ones having drifted with the tide before settling. 17. Cultivation of Oysters. — In addition to natural oys- ter-beds, there are many " oyster farms," where these deli- cious mollusks are regularly cultivated. Stakes are driven in the mud in shallow water, and branches of trees, rough boards, or stones are placed between them for the baby oysters to fasten themselves to. When the nursery is ready, several boat -loads of oysters are dropped near the spot. The oysters rapidly increase in size and nura- 148 ANIMAL LIFE IN THE SEA AND ON THE LAND. bers, and are ready for the table in from two to four years. 18. Oysters destroyed by Dredging. — Oysters are gener- ally fished with a dredge. As this instrument is dragged over the bed, the teeth pull up the oysters, both large and small, from their resting-place. Those that are too young for market are thrown back into the water, and if they fall oh a suitable surface they will again attach them- selves, and continue to grow. Many of them, however, sink in the mud and are suffocated. 19. The process of dredging is also destructive to the oysters which remain on the bed, as they are roughly torn from each other and dragged into the mud. Here they cannot open their valves without admitting the mud, and this is certain death to an oyster. 20. Oysters are highly esteemed for food on account of their delicious flavor, and the demand for them is con- stantly increasing. This leads to excessive fishing of the oyster-beds, and in many places the beds yield a much smaller supply than formerly. Such is the case with many of the European oyster-beds. The French government has been obliged to take control of those on its shores, and to enforce certain laws with regard to fishing them. MUSSELS AND PECTEXS. U9 XXIII. MUSSELS AND PECTENS. SUB KINGDOM, MOLLUSCA : CLASS, LAMELLIBRANCHIATA. 1. Marine Mussels. — Marine mussels grow in large beds in shallow water, fastened to stones and sand-banks, and making a solid black mass. They often cling to posts and piers, where they are left uncovered when the tide is low. At such times they keep their shells tightly closed, like barnacles. Fig. 89a. — Bunch of Mussel -shells. 2. The Foot of the Mussel. — The structure of mussels is similar to that of oysters, except that they have a tough foot. This is a thick, fleshy organ, which may be pushed out to a great length. In different species of mollusks the foot has various uses, enabling the animal to push it- 150 ANIMAL LIFE IN THE SEA AND ON THE LAND. self about or to leap, while often it is used for boring holes in the sand or mud. Although this organ helps some mollusks to move about from place to place, it does not resemble a real foot, but is more like a tongue. 3. The Byssus. — Mussels are hatched within the shell of their parents. After leaving the shell, and swimming around for a while, they attach themselves to some ob- ject by silken threads called byssus. At the base of the foot is a gland for secreting the fluid byssus, which, when dry, forms into brown threads not unlike the silk of spi- ders and caterpillars. The foot attaches this sticky fluid to some object, and is then withdrawn, leaving the silk fastened to the surface. Mussels are also joined to one an- other in great bunches, as well as to the bed of the ocean. 4. The threads of byssus are long enough to admit of slight motion, as the mussels float and drift back and forth, so these animals are not compelled to remain in one position, as oysters do. If the byssus is broken the mus- sels attach themselves again by other threads. 5. How strange it seems that these lowly sea-creatures should spin silk ; yet the long, fine threads of byssus have sometimes been woven into gloves and stockings, and even into cloth. 6. The fresh-water mussels have no fierce waves and tides to resist, and therefore do not secrete byssus. 7. Mussels cultivated for Food. — Salt-water mussels are used for food, and are cultivated like oysters. When the young mussels have reached the size of a small bean they are scraped in masses from objects to which they have adhered, and are carried in baskets to places suited for their growth. They soon attach themselves to posts and branches of trees prepared for them, and are transplanted in this way three times before reaching their full size. MUSSELS AND PECTENS. 151 8. The Epidermis of Shells. — All living shells have an outer layer of animal matter called epidermis ; they have no lustre upon the exterior until this epidermis is taken off and the surface is polished. Mussel-shells show beau- tiful blue tints when the epidermis is removed. 9. The Color heightened by the Action of Light. — The color of shells depends much upon the action of light, and those grown in shallow water have generally brighter col- ors than those grown in deep water. The largest and most highly colored shells are found in the tropics, whereas arctic shells are mainly small and dull. The peculiar lustre of shells is due to the minute edges of alternate layers of carbonate of lime and animal tissue. In order to fully enjoy these treasures of the ocean, we must see them under the sparkling water, where their beautiful forms and colors are heightened by " The sun, and the sand, and the wild uproar." 10. How Pearls are Formed. — Pearls are formed in shells when grains of sand lodge between the mantle and the shell and become coated with the shelly matter, or " nacre," which the mantle secretes. Fresh - water mussels yield pearls that are sometimes quite valuable, but the finest pearls are obtained from the pearl-oyster. The pearl-oys- ter in Fig. 90 is the circular shell, which has a straight hinge and one pearl clinging to it, and which is partly cov- ered by the mussel-shell. 11. Pearls mostly have a nucleus of sand in the centre, and the shelly layers are arranged around it like the coats of an onion. The Chinese take advantage of this fact, and sometimes place small images or beads inside the shell, allowing them to remain until they are coated with pearl. Some of these are shown at the right of the picture. 152 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fig. 90. — Pearl-bearing Shells. 12. Pearl Fisheries. — The most important pearl fisheries are on the coast of Ceylon. The same locality is not fished every year for fear of impoverishing it. The labor of div- ing for pearl-oysters is very severe. The divers remain un- der water only thirty seconds at a time, but they sometimes dive twenty times in one morning, and become very much exhausted. Having touched bottom, the diver gathers the oysters within reach, and places them in a net, then he pulls a cord as a signal to be drawn up immediately. At mid-day a gun sounds for the fishing to stop, and the boats are taken to the shore and unloaded before dark, in the presence of officers, so that no robbing shall be done. 13. The oysters are allowed to remain on shore until they decompose. The pearls are then easily gathered from the gaping shells, and they are worked with pow- dered nacre to give them a good polish. Pearls may be round, ovoid, or pear-shaped. Those which adhere to the MUSSELS AXD PECTENS. 153 valves are consequently irregular in shape, and, as they are not so valuable as others, they are sold by weight. Mother-of-pearl is the lustrous layer taken from the inside of the shell of the pearl-oyster. 14. Celebrated Pearls. — There are a few fine pearls so remarkable for their size and beauty as to have become historical, and their line of descent can be traced for generations. Most of these pearls belong to kings and princes. A famous string of pearls belongs to the Shahs of Persia in which each pearl is the size of a hazel-nut. 15. Pectens. — Pectens (Fig. 91) are found in all seas, and of many different varieties. Their elegant shells are ribbed and mottled with various colors, and they grow by additions made to the edge, rather than by a thickening of the valves, as in the oys- ter. The hinge is ex- tended into broad ears, and is worked by a ligament placed in a tiny pit which you can easily discover. The mantle is fringed with tentacles, and has a double row of bright spots on the edge, which are thought to be eyes. 16. Contrary to the habits of most bivalves, the pretty little pectens can swim through the water. As they are propelled by alternately opening and closing their valves, their movements consist of a succession of jerks. >7* 91. — Pecten Shell. 154 ANIMAL LIFE IN THE SEA AND ON THE LAND. XXIV. CLAMS AND RAZOR-FISHES. SUB-KINGDOM, MOLLUSCA : CLASS, LAMELLIBRANCHIATA. 1, Markings upon the Inside of a Clam-shell. — The name "clam" is applied to many different species of mollusks along our coast having thick shells. Upon looking care- fully at one of these shells you will find that it differs in many respects from the oyster- shell which we exam- ined. You will at once notice the two marks (a, a', Fig. 92) left by the muscles, and you will readily infer that the valves of clam- Fig. 92. — Inside of a Clam-shell. a, a', impressions of the muscles; p, pallial line; s, bend occupied by the siphon ; h, hinge ; c, t, t', teeth. shells must be connected by two muscles. 2. What curious freaks the pallia! line (p) has taken be- tween these two points. You can scarcely understand now why it should turn inward and make that deep bend, but when you have learned about the animal that inhab- ited this shell, the reason will be plain to you. CLAMS AND RAZOR-FISHES. 155 3. Teeth in the Hinge. — There are also peculiarities in the hinge (A) which we must not fail to observe. The spaces between the three teeth (c, t, t') are exactly fitted b}^ two other teeth in the opposite valve, and these inter- lock when the shell is closed. In some species of clams there is a large, spoon-shaped hollow at the hinge, with long ridges on each side fitting into corresponding grooves on the opposite valve. The central hollow space contains the ligament, or spring, which, as we learned in the oyster, is always trying to push open the shell. 4. Lines of Growth on the Shell. — On the outside of the shell the lines of growth are plainly seen, and you can trace the exact size of the clam at different periods of its history all the way back to babyhood. These shells do not grow thick with age. 5. Mantle attached to both Valves. — A clam, we know, always looks torn and ragged on opening the shell. It is impossible to remove the valves and leave the animal smooth and uninjured, as the oyster is when taken from its shell. This is because the mantle is attached to both valves along the pallial line, making a closed bag for fluids, which is torn when we open the shell. 6. Mantle rolled into Tubes forming a Siphon. — Water is admitted into this closed sac only through a siphon (b, c, Fig. 93), which is in reality the mantle rolled up into two tubes. Through one of these tubes a stream of sea- water enters, and, circulating under the mantle, passes down to the mouth and gills. It is then thrown out by the second tube, carrying off with it all waste matter. The circulation of water is kept up by countless cilia which line the tubes, and which, by their constant waving motion, draw the water towards the gills. 7. The tentacles at the entrance of the siphon are very 156 ANIMAL LIFE IN THE SEA AND ON THE LAND. sensitive to the touch, and keep out all floating particles except the very small ones which are suitable for food. 8. You will now understand that the curious bend (s) in the pallial line (Fig. 92) is the impression left by this siphon. 9. Organs. — The gills and the labial palpi of the clam are similar to those of the oyster. The heart is under the hinge, and, strangely enough, the intestine passes directly sr Fig. 93.— Clam (Mactra). a, foot ; b, c, siphons. through it. Clams have a tough foot (a, Fig. 93) near the mouth, by means of which they push themselves along and dig holes in the sandy beaches, and to this life they are well suited. It is surprising to see how these animals can increase their size when they wish to extend the foot, the siphon, or the edges of the mantle. This is done by taking in sea-water through numerous pores in the skin. Touch the mollusk, however, when these parts are extended, and they are quickly drawn in and the shell closed. 10. Clams lie Buried in the Mud. — Clams spend their time buried in the soft mud, with the mouth downward and the siphon extended far enough out of the shell to reach the water above. They may sometimes be seen CLAMS AND RAZOR-FISHES. 157 spouting water from small holes on the beach. It is good sport to dig them out and see how nimbly they bury themselves again in the sand, using no tool but the foot. Many clams have only a short siphon which does not ex- tend far beyond the shell. 11. Razor-fishes. — Some of these holes on the beach you may find occupied by razor -fishes (Fig. 94), which are not so easily caught as clams. These mollusks are abundant on all sandy shores, where they live buried in the mud. By means of the foot they dig a deep hole, which they do not leave. They raise themselves to the entrance of this hole, but disappear quickly upon the slightest alarm. 12. Fishermen become very expert in deal- ing with the peculiar habits of timid sea- animals, but even the fishermen find the razor-fish hard to catch, and if they fail in the first attempt to capture it, no further efforts will induce the shy creature to ap- Yig. 94. near ao-ain. Razor-shell rL , II , T! • (Solen). 13. lhe long, slender razor- shell is thin and brittle, with delicate tints of rose or violet, which are nearly concealed by the brown epidermis covering it. 158 ANIMAL LIFE IN THE SEA AND ON THE LAND. XXV. GASTEROPODS. SUB-KINGDOM, MOLLUSCA : CLASS, GASTEKOPODA. 1. Gasteropods a large Class. — Leaving the bivalves, we will now turn our attention to the gasteropods — a large class, which contains three-fourths of all living mollusks. They are found in fresh water as w T ell as in salt. Some, such as snails, live also on the land. 2. Univalves. — Gasteropods are known as univalves, since they have but one shell, which is gen- erally a tube twisted spirally from a point called the apex. A few of their beautiful forms are given in Fig. 99. In almost any collec- tion of shells you will find some of these gasteropods. By sawing one open the spiral tube may be seen winding round a central col- umn, as shown in Fig. 95, and gradually growing larger towards the opening. You will be inter- ested in tracing the coil on the outside of these shells, observing that as the occupant increased in size it made for itself more and more room in the shell. Fig. 95. — Section of a Spiral Univalve. GASTEROPODS. 159 3. Shell enlarged by Secretion from the Mantle. —We have before learned that all shells are secreted by the mantle. As the shell of the gasteropod needs enlarging, the mantle, stretching over the edge of it, deposits a layer of shelly matter, and thus the shell gains a new and larger rim. The outer edge of the mantle often contains bright-colored spots, which impart their tints to the rim of the shell, ornamenting it with bright streaks and lines. Fig. 96.— Whelk. o, operculum ; s, siphon. 4. What Forms the Spines on some Shells ? — The edges and notches of the old rim are often marked upon the outside of the shell, and there are sometimes long, bris- tling spines sticking out from them. How could these spines have been formed ? Wherever there is a spine, there must have been at that point a fold of the mantle pushed out over the rim of the shell to form a tube. This fold, like every other part of the mantle, deposited shelly matter, and finally formed the stiff spine. Of 160 ANIMAL LIFE IN THE SEA AND ON THE LAND. course, it is of no further use after the rim has grown beyond it. 5. Most of those gasteropods that have the margin of the shell notched and lengthened into a canal are flesh- eaters, whereas those having an entire and even margin live on vegetable food. 6. Gasteropods Highly Organized. — Gasteropods, as a general thing, are quite highly organized. They have a distinct head, with two tentacles, and eyes that are some- times stalked; they are believed to have the senses of hearing and of taste, also, which indicates a high- er stage of devel- opment than that of the oyster and clam. 7. Siphon — Operculum. — Water is' admit- ted within the body by means of a siphon, and at this point the shell is often lengthened into a long canal. The thick tough foot may be extended entirely beyond the shell, but gasteropods are timid creatures, and when alarmed all parts of the body are instantly drawn in, and the entrance is closed with a horny plate on the foot, which is repre- sented at o, Fig. 96. This plate fits snugly in the shell, and is called the operculum. The operculum of some gasteropods consists of limestone; small ones of this kind are known as " eye-stones," and were formerly used to re- move irritating particles of dust from the eye. 8. Lingual Ribbon. — Gasteropods have a remarkable tongue, which contains many sharp- pointed teeth set in B ^sat^ Fig. 97 -Lingual Ribbons. A, portion of tongue of Velutina, enlarged ; B, portion of tongue of whelk, magnified; C, head and tongue of limpet; D, portion of same, greatly magnified. GASTEROPODS. 161 distinct rows (Fig. 97). The growth of the tongue con- tinues during the life of the animal, new teeth forming at the base of the tongue and growing forward to take the place of those that are worn off at the tip. This tongue is spoken of as the "lingual ribbon," or as the " odontophore." 9. Shells bored by the Lin- gual Ribbon. — With the lin- gual ribbon gasteropods file holes in other shells, through which they suck out the soft body. Many strong shells that would apparently make an excellent defence are found to be pierced in this way by a round hole, the edges of which are perfectly true ing not only good tools, bat a skilful use of them (Fig. 98). 10. Shells that are washed ashore are mostly empty, and now that your attention has been called to the fact, you will be surprised to see so many bearing this round hole, and telling the sad fate of their former inmates. You will find that the hole is made near the hinge, and directly over the softest part of the body. 11. Digestion of Gasteropods. — In addition to the numer- ous teeth on the tongue of gasteropods there are hard plates in the stomach for crushing food. After being mixed with saliva, which is furnished by salivary glands, the food passes through a long oesophagus into the stom- ach. Here the food is acted upon by fluids secreted by the liver and other glands. It then passes into a long intestine, where the nourishing portions are absorbed into Fig. 98. — Clam-shell bored by Lin- gual Ribbon of Gasteropod. and even, indicat- 162 ANIMAL LIFE IN THE SEA AND ON THE LAND. g^ the blood, and sent with it to all parts of the body by the beating of the two-celled heart. Fijc. 99. — Sea-shells. GASTEROPODS. 163 12. Breathing. — Gasteropods breathe either by lungs or by gills, some of them coming frequently to the sur- face of the water for air. They push themselves along by the foot, and many of them swim freely through the water. 13. Clusters of Egg-cases.— On the sea-shore we find many singular-look- ing objects, whose appearance alone would give us no idea of their real character. This is true of the odd- shaped egg-cases of many gasteropods. Fig. 100.— Egg-cases of Whelk. Among these are the eggs of the whelk (Fig. 100), which are found united in large masses, each egg in the cluster be- ing enclosed in a little sac of its own. 14. Many of you have picked up on the sea-shore lon^ strings of the egg-cases of the pear-conch (Fig. 101). These are very common on sandy beaches. They are composed of many cream - colored cases, or capsules, of a tough, leathery sub- stance, which diminish in size tow- ards both ends of the string. 15. They contain eggs which hatch within the capsule, each little conch being provided with a tiny shell. After consuming the jelly- like fluid with which the capsule is filled, the animals work their way out of the leathery ba^ and burv themselves in the sand. Fig. 101. — Egg -cases of Pear-conch. 164 ANIMAL LIFE IN THE SEA AND ON THE LAND. 16. If you examine the cases you will find a little round hole on the top of each one, which is closed by a gristly substance, and looks as if it were provided as an easy means of escape for the young conchs. Cut open a case, and if the little occupants have not already escaped, you will find it filled with lovely shells. 17. The Nidus of the Natica.— One of the sea -snails (the natica, Fig. 102) makes a ring-shaped nest, or " nidus," of fine grains of black and white sea - shore sand, glued together by the slimy substance in which the eggs are deposited. This nidus (Fig. 103) when first taken from the water is soft and leath- ery, but it becomes exceedingly brittle when dry. It somewhat resembles the broad rim of an old felt hat, and its surface is often thickly studded with the egg -capsules of another gasteropod, the nassa, which avails itself of this convenient place of deposit for its eggs. Fig. 103. — Egg-case of Natica. LIMPETS AND LAND SNAILS. 165 XXVI. LIMPETS AND LAND SNAILS. SUB-KINGDOM, MOLLUSCA : CLASS, GASTEROPODA. 1. Limpets. — Limpets are attractive little gasteropods living on those parts of the sea-shore which are left un- covered at low tide. Our best time to watch them will be when the shallow water is rippling over their bodies, and their conical shells are lifted that they may enjoy the full benefit of the bath. 2. The Shell. — The univalve shell, you will observe, is not spiral, but is a simple oval shell, tapering to a point on the top like a tent. This shape gives great strength to the shell, and enables it to support a heavy weight without injury. The exte- rior of the shell is a dull gray col- or, without much ornamentation, Fig. 104.— Limpet-shell. but the interior is peculiarly smooth and lustrous, and is prettily marked by the pallial line. 3. When under water, limpets move about slowly by means of a round foot, but as their gills cannot long bear exposure to the air, when the tide is out their shells are drawn down close to the rock and held there tightly. 4. Limpets adhere firmly to the Rocks. — The foot has some power of adhering firmly to surfaces as if it were glued, and when the limpets are alarmed they hold on so 166 ANIMAL LIFE IN THE SEA AND ON THE LAND. tightly that it is difficult to remove them. In attempting to pry them off, the shell is often broken before they let go their hold. Limpets sometimes remain so long in one spot that the rock is hollowed out to their exact shape. Sea-birds are fond of eating them, and are so cunning as to thrust their bills under the shell when it is lifted. 5. How Limpets Eat. — The limpet's head is furnished with a pair of eyes and a pair of tentacles. The lingual ribbon is covered with sharp teeth set in three rows, and is three times the length of the entire animal. Limpets feed upon sea-weed, sometimes making a noise with the tongue as it strikes upon the hard upper jaw in biting. 6. A Large Limpet. — The limpets in tropical seas are larger and richer in color than ours. One species is found at the Strait of Magellan having a shell nearly a foot in width, which is used by the natives as a basin. 7. Snails. — Limpets furnish us an example of gastero- pods that live partly out of water, but their cousins, the snails, which we will next consider, have gone a step farther and live altogether on land. 8. It is amusing to watch the motions of these curious snails as they crawl about with their great shell houses on their backs, stretching out their feelers, then suddenly drawing them in again. All at once some fancy seems to strike these uncertain individuals, and the whole slimy dark-gray body is pulled back into the shell. 9. The Shell. — The shell is remarkably light and delicate, and you may easily trace the coil upon the outside. In some species the edge is plain and sharp, while others have the edge folded back to make a smooth, firm border. 10. Senses of Sight and Smell. — Snails are better trav- ellers than limpets, and far more active. Like them, they have a foot and a lingual ribbon. Besides the long tenta- LIMPETS AND LAND SNAILS. 107 Fig. 105. — Anatomy of a Snail. a, month; b, foot; c, anus; d, lung; e, stomach, covered ahove hy the salivary glands; /, intestine; g, liver; h, heart; i, aorta; j, gastric artery; k, artery of the foot; I, hepatic artery; m, abdominal cavity; n, irregular canal communi- cating with the abdominal cavity, and carrying the blood to the lung; o, vessel carrying the blood from the lung to the heart. cles tipped with black eye- specks, snails have a shorter pair, which, it is thought, are organs of smell. This lat- ter sense is apparently more keen than their sight, since they are attracted by odors of fruit and vegetables, though they do not seem to see obstacles placed in their way. 11. The Breathing Organ. — The breathing organ of snails is a chamber lined with a net-work of blood-vessels {d, Fig. 105), and supplied with air by a small orifice which may be seen to open occasionally. The air is then ex- pelled from this chamber by drawing the body into the narrow part of the shell. 12. Where Snails Live. — Snails delight in warm, damp weather, and they may be easily found in shady places in the woods. When winter comes they hide in the ground, and close their shells with successive layers of mucus, which, when dry, form a hard membrane over the opening. Their eggs are laid loose under damp leaves and stones. 168 ANIMAL LIFE IN THE SEA AND ON THE LAND. 13. These land mollusks have perhaps gradually ac- customed themselves to living, first in marshes, then in damp, swampy places, until finally we have some species living entirely upon dry land. Still, their favorite spots are the shady, moist ones. 14. Snails eaten for Food. — In many parts of Europe snails are eaten for food, and they are sometimes painted on the sign -boards of restaurants and drinking shops. Fig. 106. — An Edible Snail. They were considered a delicacy by the ancient Romans, who served them at their funeral entertainments. In the buried city of Pompeii, among other curious relics, heaps of snail - shells, which are the remains of these funeral feasts, are found in the cemetery. 15. Young Snails. — Common snails kept through the winter in the damp earth of our window plants will prove a source of great interest. In the spring they de- posit tiny white eggs, so delicate as not easily to be lift- ed. On breaking one, a perfect little snail-shell may be seen within. Later on we have the gratification of see- ing the young snails start off for themselves, creeping up LIMPETS AND LAND SNAILS. 169 and down over the rough places, and performing, on a small scale, all the manoeuvres of their elders. THE HOUSE-KEEPER. " The frugal snail, with forecast of repose, Carries his house with him where'er he goes ; Peeps out, and if there comes a shower of rain, Retreats to his small domicile amain. Touch but a tip of him, a horn, 'tis well — He curls up in his sanctuary shell. He's his own landlord, his own tenant ; stay Long as he will, he dreads no quarter-day ; Himself he boards. and lodges; both invites And feasts himself; sleeps with himself o' nights. He spares the upholsterer trouble to procure Chattels ; himself is his own furniture, And his sole riches. Wheresoe'er he roam, Knock when you will, he's sure to be at home." Charles Lamb. 170 ANIMAL LIFE IN THE SEA AND ON THE LAND. XXVII. THE OCTOPUS, OR DEVIL-FISH. SUB - KINGDOM, MOLLUSCA : CLASS, CEPHALOPODA. 1. Cephalopods. — The only group of mollusks remaining, which we will study here, is that of the cephalopods — a group which contains the most highly organized animals among the mollusks. The name cephalopod is derived from two Greek words which mean feet on the head. To this class belong the octopus, cuttle-iish, squid, etc. Fig. 107. — Octopus. 2. The Body covered with a thick Mantle. — With the ex- ception of one variety, cephalopods have no shell. The body is covered with a thick bag or mantle, which is THE OCTOPUS, OR DEVIL-FISH. 171 beautifully spotted, and which possesses the power of changing its color. The color is generally a mottled brown, but when irritated it changes to a reddish or pur- ple hue, passing rapidly from one tint to another. 3. The nearest Approach to a Brain. — The head is dis- tinct from the rest of the body, and contains nervous ganglia, protected by a cover- ing of cartilage, which is the nearest approach we have seen to the brain of vertebrates. The large staring eyes are likewise more nearly perfect than any we have yet found. 4. The Arms. — The eight arms, or feet, whichever we choose to call them, surround- ing the mouth are the most striking feature of the octopus (Fig. 107). They sometimes grow to a great length, and they have two rows of suckers on the underside (Fig. 108), which adhere so firmly to ob- jects within their reach that these animals are dangerous foes. Fastening the suckers to their prey, they draw it down to their mouths, and hold it firmly until it is torn in pieces. 5. The Parrot's Beak. — The mouth opens into a throat which is well supplied with implements for crushing food. In addition to a lingual ribbon, here are two large horny teeth, w r hich from their shape are known as the " parrot's beak" (Fig. 109). Fig. 108. — Suckers on the Arm OF A ClJTTLK-FISH. a, hollow axis of the arm, contain- ing nerve and artery; c, cellular tissue ; d, radiating fibres ; h, raised margin of the disk around the ap- erture /, g, which contains a re- tractile membrane, or "piston," i 172 ANIMAL LIFE IN THE SEA AND ON THE LAND. Fig. 109. — The Parrot's Bkak. 6. The Funnel. — The mantle is open at the neck, and ex- pands to admit water to a chamber lying within, which contains the gills. The rim of the mantle then closes by powerful muscles, and the body con- tracts, and forces the water out in a jet through the " fun- nel." This funnel is a tube provided with a valve which closes after the water has escaped, and allows no water to enter through it from the outside. 1. The Ink-bag. — Within the body is a sac containing an ink -like fluid which these animals throw out also from the funnel when they are alarmed. The surrounding water is thus discol- ored with a dense black cloud, and the octopods are en- abled to escape from their enemies. This ink is some- times used in water -color painting under the names of sepia and India-ink. The contents of the ink-bags ob- tained from fossil octopods have sometimes been dis- solved, and still they yield sepia of a good quality. 8. Octopods found in most Seas. — Octopods are found in most seas, those living in mid-ocean sometimes being very large. Within the last few years some large sj)ecimens have been taken on the Newfoundland coast. Wonderful stories are told of octopods, but it is difficult to know how much of fable may have been interwoven with the truth. We at least know that they are active creatures, often THE OCTOPUS, OK DEVIL-FISH. 173 jumping out of the water, and that they have a strange fashion of swimming backward. 9. Manner of Propelling Themselves. — Their only means of propelling themselves is by forcing water out of the funnel, the successive jets driving them backward, while the long arms trail uselessly after them. They also walk head-downward, with the rounded body above. 10. Destroying Life. — They spend much of the time part- ly concealed by the rocks, with their arms floating round in search of some- thing to kill, for they are extremely greedy, destroy- ing large numbers of fishes, crabs, and mollusks. Like the tiger, they seem to find pleasure in killing more than they need to eat. Their hid- ing-places are sometimes dis- covered by the number of dead shells scattered about. Octopods likewise are de- stroyed in large numbers by porpoises and whales. 11. The Cuttle-fish.— The cuttle-fish (Fig. 110) is much like the octopus, but it has two tentacles longer than the arms, with club-shaped ends. There are also narrow fins at the side of the body, and the mantle is supported on the inside by a thin plate which is known, as the cuttle-fish bone. Cuttle-fish bones are Fig. 110. CCTTLE-FISH (ONE - FITTH Natural Size). 174 ANIMAL LIFE IN THE SEA AND ON THE LAND. commonly used in bird-cages. If you examine one care- fully you will find it has no resemblance to true bone, being formed of layers, as shells are, with a hard cover- ing. As the captive bird pecks at this it obtains small particles of lime, which substance is needed for forming its bones. 12. Cuttle-fishes do not lie concealed in caves waiting for their prey, but they come out boldly, and give their victims a fair chance. 13. The Eggs in Bunches. — The octopus and cuttle-fish both attach their eggs by a cement secreted within their bodies to branches of sea- weed, where they hang like bunches of grapes. The moth- er sometimes selects a snug retreat in the rocks for rais- ing her young family, and barricading the entrance with pieces of rock or piles of shell, she allows no one to enter. 14. She is said to examine her eggs and rub them, some- times syringing them with her funnel, as if to keep off parasites. In about five weeks the eggs are hatched. The little creatures are about the size of a grain of rice, with eight points from which the arms will grow, and they already have the power of changing their color. The mother is much exhausted after her long confinement, her nourishment the while not having been sufficient. Fig. 111.— The Squid. THE OCTOPUS, OR DEVIL-FISH. 175 15. Used as Food. — In many countries these evil-looking creatures are used for food. They are highly esteemed on the shores of the Black Sea, for, as they are neither meat nor fish, they can he eat- en during the long fasts of the Greek Church. 16. In Southern Italy the octopus is taken alive to mar- ket, and displayed in large tubs filled with sea -water. Here the animals writhe and twist their arms, and display their dread suckers. They all look straight in front of them with their great eyes, and at frequent intervals dis- Fi charge water violently from their funnels in short, quick jerks. When a purchaser has selected one, the salesman seizes the octopus by the neck, and kills it by a skilful twist. 17. The Squid. — The squid (Fig. 112) is another one of the cephalopods. It is found in great numbers along the sea-shore, and is very generally used for bait in cod- fishing. 18. The eggs of the squid are enclosed within pod- shaped masses of stiff jelly, many of which are clustered together in one bunch. These pod-shaped pieces of jelly are sufficiently transparent to show the presence of many small eggs when held up to the light. 112. — Egg-cluster of Squid. 176 ANIMAL LIFE IN THE SEA AND ON THE LAND. XXVIII. THE ARGONAUT. SUB-KINGDOM, MOLLUSCA : CLASS, CEPHALOPODA. 1. The Argonaut. — The argonaut, or paper-nautilus, is regarded as one of the most beautiful objects in the ocean. Who would have thought of finding a celebrated beauty in the same family with the disagreeable octopus ! The charm must certainly be due to that lovely white shell which is prettily ribbed and fluted, and so transparent as to show the varying silver and rose tints of the body underneath. 2. Resemblance to the Octopus. — Notwithstanding these attractions, our eyes are now sufficiently trained to find in the argonaut many points of resemblance to the octopus. There are the unmistakable suckers on the arms, the great wide-awake eyes, and the curious funnel projecting be- yond the shell just below them. 3. The Shell secreted by the broad Arm. — In addition to these, there are many new points of interest. You will notice in the upper figure of this picture that the two hinder arms are spread out into flat, sail-like membranes, which here only partly cover the shell. They may, how- ever, be extended so as to cover it entirely. Indeed, the shell has been secreted by these broad membranes, and if it is broken in any way, the injuries are soon repaired by new shelly matter deposited just where it is needed. Fig. 113. — Argonauts. THE ARGONAUT. 179 4. The Body not fastened to the Shell. — Although the argonaut lives in this shell, its body is nowhere fastened to it, neither does it fit the shell and fill it up, as other mollusks do. It merely sits in the graceful shell as in a boat, and holds on by its webbed arms. 5. Fanciful Stories. — Fanciful stories have been told of the argonauts, and persons were led to believe that they sailed over the waves, with their webbed arms held aloft as sails to catch the breezes, and that their straight arms were used as oars. So far from sailing in this fantastic fashion, the argonaut rarely comes to the surface, but passes its days in deep water or upon the bottom of the ocean. Here it crawls head-downward, with its shell over its back, using its arms in place 'of feet. 6. In reality the argonaut swims just as its relatives do — by squirting itself backward. Gathering the arms to- gether in a straight line, as shown near the middle of Fig. 113, it takes in sea- water under the mantle, and for- cibly expels it from the funnel. 7. How snugly the lowest one in the picture has tucked itself away in the shell ! Still, it has an eye for all that goes on around it. 8. A Dainty Shell for a Cradle. — The charming part of our story has yet to be told, for you must know that these dainty shells are merely nests, with which the females are provided to protect themselves and the bunches of eggs which they carry. The young ones are hatched in this lovely floating cradle, and are thus shielded from many dangers to which they would be exposed in the open sea. In the middle figure you may see the large bunch of eggs on top of the shell and partly concealed by the body of the parent. 9. The Male Argonaut. — The male argonaut is very un- 180 ANIMAL LIFE IN THE SEA AND ON THE LAND. like the female. Not being more than an inch in length, and having no shell, it was not recognized until quite re- cently as the mate of the handsome paper-nautilus. 10. Habits Unknown. — These animals live in tropical seas, but their shells have sometimes been washed on our own shores. It is impossible to know the habits of such deep-sea dwellers, since their haunts are completely hid- den from our view. 11. Argonauts have interested thoughtful men from a very ancient date. Their appearance on the water was welcomed as an indication of fine weather, and one of the Greek poets long ago wrote, "O fish, justly dear to navi- gators ! thy presence announces winds soft and friendly ; thou bringest the calm, and thou art the sign of it." THE PEARLY NAUTILUS. 181 XXIX. THE PEARLY NAUTILUS. SUB-KINGDOM, MOLLUSCA : CLASS, CEPHALOPODA. 1. The Pearly Nautilus. — The most interesting of all the cephalopods is perhaps the pearly nautilus. Unlike other members of its class, this animal is supplied with a true external shell, which is divided into many chambers ; hence, it is often called the " chambered nautilus." 2. The Chambered Shell. — In its natural condition the outside of the shell resembles white porcelain streaked with reddish-brown stripes. The nautilus shells usually seen in cabinet collections have been polished ; this out- side striped coating has thus been removed, and nothing remains but the lustrous pearl underneath. 3. The shell is elegantly shaped and proportioned, but gives no hint of the curious arrangement inside until it is cut open. It is then found to contain many chambers partitioned off by curved, pearly plates which you can readily see in Fig. 114. The animal always occupies the outer and larger chamber, as here represented, retiring from it in its turn and walling it up as the shell increases in size to meet the needs of the growing body. 4. In this way each chamber has been successively the home of the nautilus, and has been abandoned when it ceased to be desirable. 182 ANIMAL LIFE IN THE SEA AND ON THE LAND. " Year after year beheld the silent toil That spread his lustrous coil ; Still, as the spiral grew, He left the past year's dwelling for the new, Stole with soft step its shining archway through, Built up its idle door, Stretched in his last-found home, and knew the old no more." 5. The Siphuncle. — There is a curious tube, or "si- phuncle," extending from the body through all the cham- bers to the end of the coil. Its use is not positively known, although it may be instrumental in compressing the gas Fig. 114. — Pearly Nautilus, with Shell cut open (one-half Natural Size). with which the chambers are probably filled, thus affect- ing the weight of the shell, and enabling the animal to rise or sink in the water when it wishes. 6. Means of Swimming. — Our beautiful nautilus has dis- covered no more graceful means of swimming than by ex- THE PEARLY NAUTILUS. 183 pelling water from the funnel, as others of its family do, but it has not their peculiarity of squirting ink, insomuch as it possesses no ink-bag. 7. The Organs. — It has many short arms, which are high- ly sensitive, but which have none of the suckers so remark- able in the cuttle-fish. The mantle is thickened into a leathery fold or hood over the head, which closes the shell when the animal retires within it. 8. The mouth is surrounded by a fleshy lip and several additional folds, and it opens into a cavity where the par- rot's beak and the lingual ribbon are situated. The eyes are attached by short stalks to the sides of the head. 9. Living Specimens rare. — Although nautilus shells are quite common, only a few specimens of the animal have ever been obtained ; from which fact it is inferred that the nautilus lives only at great depths, in tropical regions of the Pacific and Indian oceans. Unfortunately, we know almost nothing of its habits. 10. The Last of its Race. — The nautilus is especially in- teresting, since it is the last member of a once numerous race of four-gilled cephalopods with external shells, which formerly oc- cupied the seas. Entire families have ceased to exist, and are known to us only by fossil remains, which are very abundant in the rocks, more than two thousand species being known. 11. Ammonites.— Among the most interesting of these are the ammon- ites, one of which is shown in Fig. 115. Their chambered shells are much like nautilus shells, but instead of having partitions with plain edges, the partitions are folded and Fiu;. 115. — Ammonite. 184 ANIMAL LIFE IN THE SEA AND ON THE LAND. crinkled, forming curious patterns on the outside of the shell. Ammonites evidently lived in the deep sea. They are found of all sizes, varying from an inch to more than a yard in diameter. 12. These ancient four-gilled forms have been succeeded by the two-gilled cephalopods (such as the octopus and cut- tle-fish) without shells, which now monopolize the ocean. The beautiful nautilus has gradually decreased in num- bers, and will probably become extinct also, as the rest of its family have done. BACKBONED ANIMALS. 185 XXX. BACKBONED ANIMALS. SUB-KINGDOM, VETCTEBRATA. 1. The Backboned Family. — An important point in our studies is now reached, and we are about to enter upon that great sub-kingdom which is spoken of as the " back- boned family." The animals comprised in this large fam- ily differ so greatly from the Radiates, Articulates, and Mollusks, which we have been studying, that it seems necessary to pause here and examine some of their pecu- liarities. 2. We shall find among the backboned animals a great variety of forms and habits ; still, we can trace in their physical structure an unbroken se- ries, and passing regularly up from the lower forms of this type, we shall gradually approach animals that are highly endowed with in- telligence and strength. Fishes, we know, live only in the water. So Fig . n 6.- A Vertebra. also do frogs and toads during the a> spina] caua] early part of their lives, but after they become fully matured they mostly live on the land, and have many points of resemblance to reptiles. In turn, the reptiles lead on to birds, which, by their pecul- iar strength and lightness, are fitted to live almost wholly 1SG ANIMAL LIFE IN THE SEA AND ON THE LAND. in the air. Last of all are the mammals, whose superior endowments crown the list. 3. The Spinal Column. — The most important peculiarity of this family is that the greater part of its members possess a "backbone," or, more properly speaking, a spinal BACKBONED ANIMALS. 18' column, which is composed of a chain of small bones or vertebrae. Owing to this fact, the name Vertebrata has been given to the sub-kingdom. The vertebrae are united side fiy side by means of ligaments, and as each vertebra has an opening through its centre, as is shown at a, in Fig. 116, the chain forms a continuous canal throughout the entire length of the spinal column. 4. The two Tubes of Vertebrates. — In the spinal canal, which we have just de- scribed, lies the spinal cord, safely en- cased in bone, and connecting with the brain through an opening in the lower part of the skull. You will observe, therefore, that the brain and the spinal cord, the large masses of the nervous system, are shut off by a special tube from other parts of the body. 5. Carrying this idea yet further, we will now consider the main cavity of the body, which (as in the lion, Fig. 117) is formed by the ribs, the back- bone, and the breastbone, as a second tube for containing the heart, lungs, stomach, etc. 6. The distinction between Vertebrates and Invertebrates. — This especial pro- vision for the nervous system is the great distinction between vertebrates and those animals having no spinal col- umn, which are called invertebrates. The body of inver- tebrates may be looked upon as one single tube, in which the nervous system is not separated from other organs ; Fig. 118. — Human Brain and Spi- nal Cord send- ing off Xerves. 188 ANIMAL LIFE IN THE SEA AND ON THE LAND. whereas, the body of vertebrates consists of two distinct tubes, one for the large, nervous masses, the other for the organs of digestion, circulation, etc. 1. The Nervous System. — The brain, lying within the skull, and the spinal cord proceeding from it, are the great centres which give rise to the symmetrical pairs of nerves passing to all parts of the body (Fig. 118). These nerve- Fig. 119. — Arm and Leg of a Man as they are Seen when on All-focrs. S, scapula; I, ilium, or ehinbone of pelvis; H, humerus; F, femur; O, olecranon, or tip of the elbow; P, patella; U, ulna; T, tibia; R, radius; Fi, fibula; Po, pollex, or thumb ; 11a, hallex, or great toe. centres are, as we have seen, well protected by the won- derful chain of bones constituting the spinal column. In addition to this arrangement, there is a series of nerves supplied to the thorax and abdomen known as the sym- pathetic nerves, which regulate the digestion, respiration, and the circulation of the blood. 8. The Skull. — That strong, bony box which we call the BACKBONED ANIMALS. 189 skull not only contains the brain, but it also protects the delicate organs of sight and of hearing, as well as those of taste and smell, all of which are lodged in its bony cavities. 9. The Skeleton. — Another peculiarity of vertebrates is that they possess a jointed skeleton which is always in- ternal. The hard bones composing this skeleton are not dead and lifeless, as they look to be, but they undergo a continual change, since they are nourished by the blood which, in its circulation through the bony tissues, carries off all the waste particles, and deposits new materials for their growth and repair. 10. The Limbs. — Animals of this family never have more than two pairs of limbs, and these are joint- ed and turned away from the back. By far the great- er number of vertebrates are supplied with both pairs of limbs ; still there are some animals, as for instance the whale, in which the limbs are only partially developed, and others again, like the snake, in which the limbs are altogether wanting. 11. As the limbs of different animals are employed for a great variety of purposes, we shall find that they are curiously modified to serve these various uses, yet a simi- larity may be observed in the structure of all. Thus the fore -legs of quadrupeds are represented by the arms of man, by the wings of a bird, and by the swimming-pad- Fig. 120. — Hind-leg of Alligator and Fore-leg of Seal. S, scapula ; I, ilium, or shinbone of pel- vis ; H, humerus ; F, femur : O, olecra- non, or tip of the elbow; IT, ulna; T, tibia ; R, radius ; Fi, fibula ; Po, pollex, or thumb. 190 ANIMAL LIFE IN THE SEA AND ON THE LAND. dies of a whale. If you should compare the arm of a man with the leg of a seal or the wing of a bat, as repre- sented in the accompanying figures, you will discover a close resemblance between them. 12. The Digestion of the Food. — All vertebrates have a mouth, which generally is furnished with teeth. The food is mostly cut and divided in the mouth and mixed with saliva, after which it is swal- lowed and digested, and the nutritious portions are ab- sorbed into the blood. 13. The Heart.— The heart of all vertebrates contains at least two chambers, and in the higher classes of animals it has four distinct chambers. These chambers are supplied with valves at their openings which allow the blood to pass through, but which close in such a manner as to prevent its return in the opposite di- rection. 1 4. Circulation of the Blood. — Dr. Harvey, in 1619, was the first person that taught the great fact of the circula- tion of the blood, and it is now so well understood as to attract but little attention. We know that the blood of living animals is continually flowing to every part of the body through closed tubes, or blood-vessels, as they are called, the arteries being employed in carrying it from the heart, and the veins in returning it again. 15. The Blood. — We are accustomed to think of the Fig. 121. — Fore and Hind Leg of a Tapir. S, scapula; I, ilinm, or shinbone of pelvis; H, humerus; F, femur; O, olecranon, or tip <>f the elbow ; P, pa- tella; U, ulna; T, tibia; R, radius; Fi, fibula. BACKBONED ANIMALS. 191 blood simply as a red fluid, whereas, upon examination, it is found to be a clear liquid, almost without color, in which floats a multi- tude of minute par- ticles or "corpuscles," so exceedingly small that they can be dis- covered only with a powerful microscope. Some of these corpus- cles are red, others are white. The red corpuscles have a ten- dency to run togeth- er into piles like but- tons on a string, and they are so numer- ous as to tinge the blood with their red color (Fig. 122). 16. The Breathing of Vertebrates. — We shall find a great difference among these animals with regard to their man- ner of receiving a supply of fresh air. Fishes and am- phibious animals are furnished with gills, and derive their supply of air from the water, but the higher vertebrates breathe by true lungs, and the process of airing the blood is greatly assisted by the action of the skin. Fig. 122. — Blood Corpuscles of Man. 192 ANIMAL LIFE IN THE SEA AND ON THE LAND. XXXI. FISHES. SUB-KINGDOM, VERTEBRATA : CLASS, PISCES. 1. Fishes. — It is not an easy thing to study the every- day life of fishes. Living as they do in the water, and keeping out of sight, our only hope of observing them is from an occasional glimpse, which gives us little oppor- tunity to learn their habits and peculiarities. Preserved specimens are of no great help ; they serve, however, to remind us that much of the charm of fishes lies in the grace of their movements and in the delicate lustre which plays upon their sides as they glide through the water, but which is lost soon after death. 2. Fishes are well adapted to Swimming. — The shape of fishes is such as to admit of their swimming easily and smoothly through the water with. the least possible fric- tion. They are further aided in swimming by their smooth, slimy coating, which generally consists of scales overlapping one another like tiles on a roof. 3. Dr. Hartwig says of fishes : " We wisely endeavor to imitate this peculiar form in the construction of our ships, yet the rapidity with which the fastest clipper cleaves the waters is nothing to the velocity of an animal formed to reside in that element. The flight of an arrow is not more rapid than the darting of a tunny, a salmon, or a gilt- head through the water. Every part of the body \ z r-—^m l