1 ■ i ^^^!^^ H W: mvo fork i>tatE ClfaUBge of Agritulturc At (Cornell MniwEreita Jtljaca, £f. 5. Htbratg Cornell University Library QL 48.C77 Animal life in the sea and on the land.A 3 1924 003 407 354 Cornell University Library The original of tliis book is in tlie Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003407354 The Kins of Beasts. ANIMAL LIFE IN THE SEA AND ON THE LAND A ZOOLOGY FOB YOUNG PEOPLE By SAEAH cooper ILLUSTRATED j^^e NEW YORK ■ : • CINCINNATI • : ■ CHICAGO AMERICAN BOOK COMPANY Supplementary Reading for Elemen- tary Grades. Aih a( hTi:!v Illustrated. ^ 67*7 a Rlckoff s Supplem ntary First Reader. 1 22 pages. 25 cents. Book of Cats and Dogs and Other Friends. (First reader grade ) 96 pages. 17 cents. Friends in Feathers and Fur, and Other Naigh- bors. {Second reader grade.) 140 pages. 30 cents. Neighbors with Wings and Fins, and Some Others. (Third reader grade.) 230 pages. 40 cents. Some Curious Flyers, Creepers and Swimmers. (Third reader grade.) 220 pages. 40 cents. Grandfather's Stories. (First reader grade.) 137 pages. 27 cents. Stories of Heroic Deeds. > second reader grade.) 151 pages. 30 cents. Stories of Our Country. (Third reader grade.) 207 pages. 40 cents. Stories of Other Lands. (Third reader grade.) 232 pages. 40 cents. Easy Steps for Little Feet. (First reader grade.) 1 J'^ pages. 25 centb. Golden Book of Choice Reading. (Second reader gr.tde.) 192 pages. 30 cents. Book of Tales. (Third reader grade.) 272 pages. 50 cents. Familiar Animals and Their Wild Kindred. (Third reader grade.) 208 pages. 50 cents. Living Creatures of Water, Land and Air. (Third reader grade.) 20S pages. 50 cents. n®"Any book on this list mailed to any ad- dress on receipt of price. Write for descriptive circulars. Copyright, 1887, by Harper & Brothers. Alt riyhtfi ret^erved. COOPER AN. LIFE, E-P 6 TO THE ENTHUSIASTIC CLASSES FOK WHICH THE LESSONS WERE PREPARED THIS BOOK is 1.ffectionoteln ?Debicateb 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 throughout. 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. PASE I. Sponges 1 II. Htdkoids 13 III. Jelly-fishes 18 IV. The "Portuguese Man-of-war." 26 V. Sea- anemones 39 VI. Corals 36 VII. Coral Beefs 43 VIII. Ctenophora 49 IX. Star-fishes 56 X. Sea-urchins 63 XI. Crlnoids, or Stone-lilies 70 XII. Sea-cucumbers 76 XIII. Earth-worms 83 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 Pbctens 149 XXIV. Clams and Eazor-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 193 VIU CONTENTS. PAGE XXXII. The Migration op Fishes 205 XXXIII. Fkogs and Toads 311 XXXIV. Turtles 217 XXXV. Snakes 223 XXXVI. Lizards 230 XXXVII. Cbocodilbs , 23o XXXVIII. Characteristics of Birds 243 XXXIX. Birds' Eggs and Nests 353 XL. Swimming-birds (Natatorea) 260 XLI. Wading-bikds (Cr/'aKatores) 271 XLII. Running-birds (Cursores) 277 XLIII. ScRATCHLNG-BiRDS (Basores) 284 XLIV. Olimbing-birds {Si-annores) 295 XLV. Pebching-birds (Iiisesmres) 302 XLVI. Birds of Prey (Haptores) 320 XL VII. The Ornitiiorhykchus 327 XLVIII. Kangaroos and Opossums 333 XLIX. Sloths, Armadillos, and Gre.vi' 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 383 LVII. Beavers and Squirrels 387 LVIII. Bats 395 LIX. Monkeys 398 LX. Man 406 ILLUSTRATIONS. The King of BeaBts Frontispiece. PIG. 1. 2. 3. i. 5. 6. 1. 8. 9. 10. 11. 12. 13. 14. 16. 16. 17. 18. 19. 20. 21. PAGE Sponge 1 Sponges Growing 2 Groups of Spicules 3 Circulation of Water through the Sponge 4 Living Sponge in Action. . , 4 Neptune's Glove 6 Venua's Flower-basket 1 Sponge-fiahing 9 Glaas Sponge 10 Hydroids growing on a Shell 12 Hydroid Magnified, showing Spore-sacs 14 Jelly-fish {Aurelia Aurita), with Young in various Stages 16 Section of Jelly-fish, showing Tubes and Mouth 18 Jelly-fish (Cyancea 3nploca- mia) 19 Lasso-cells from a Fresh-wa- ter Hydroid (magnified). . 20 Mushrooms of the Sea 23 Group of Phoaphorescent An- imals 24 " Portuguese Man-of-war ". . 28 Stomach and Chambers of Sea-anemone 30 Cluster of Anemones 32 Sea-anemones 34 FIG. PAGE 22. Branching Coral Alive, with Polyps expanded 37 23. AstriBa Pallida (natural size) 39 24. Mushroom Coral 40 25. Organ-pipe Coral 41 26. Fragment of Red Coral with Polyps 42 27. Formation ot 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. ... 66 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 {Pentada 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 Vulgarh) 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 Eyes, and Antennse Ill 68. Alimentary Canal of a Bee- tle 112 69. Tracheae of an Insect, show- ing Elastic Spiral Thread 112 70. Butterflyin the Larva, Pupa, and Imago State 113 FIG. PAGE 71. Scales on the Wing of a Moth 114 72. Butterflies 115 73. Moth and LarvEO 117 74. Wings of a Bee, showing the Hooks 119 75. A Bee's Sting 120 76. Nest of Carpenter-bee 120 77. Nest of Humble-bee 121 78. Hive -bees ,. . 122 79. Little Plunderers 123 80. Digger-wasp — Cocoon and Larva 128 81. Nest of Mud-wasp 129 82. Nests of Social Wasps.. . . 130 83. Hornets' Nest 131 84. Different Stages in the Growth of a Mosquito.. 133 86. Ant Nest, with Under- ground Passages 136 86. Larva, Cocoon, and Pupae of Red Ant (magnified) . . 137 87. Slave-making Ant (magni- fied) 138 88. Queen of Slave - making Ants (magnified) 141 89. Oyster in the Shell (with mantle removed from the upper surface) 1 44 89a. Bunch of Mussel-shells.. 149 90. Pearl-bearing Shells 15-2 91. Pecten Shell 153 92. Inside of n Clam-shell 154 93. Clam (Maetra) 156 94. Razor-shell (Solen) 157 95. Section of a Spiral Uni- valve 158 96. Whelk 159 97. Lingual Ribbons 160 98. Clara-shell bored by Lin- gual Ribbon of Gaster- opod 161 99. Sea-shells 162 ILLUSTRATIONS. XI PIG. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 130. 131. PAGE Egg-cases ofWhelk 163 Egg-cases of Pear-conch. 163 Natica 164 Egg-case of Natica 164 Limpet-shell 165 Anatomy of a Snail 167 An Edible Snail 168 Octopus 170 Suckers on the Arm of a Cuttle-fish 171 The Parrot's Beak 172 Cuttle-fish (one -fifth nat- ural size) 173 The Squid 174 Egg-cluster of Squid .... 175 Argonauts 177 Pearly Nautilus, with Shell cut open (one-half nat- ural size) 182 Ammonite 183 A Vertebra 185 Skeleton of a Lion 186 Human Brain and Spinal Cord sending off Nerves 187 Arm and Leg of a Man as they are Seen when on All fours 188 Hind-leg of Alligator and Fore-leg of Seal 189 Fore and Hind Leg of a Tapir 190 Blood Corpuscles of Man . 191 Nest of the Sun-fish 193 The Fins of a Fish (pike- perch) 195 Anatomy of the Carp. . . . 197 Plan of Circulation in Fishes 198 Flying-fish 199 Nest of the Stickleback. . 200 The Sea-horse 201 Shark 202 Esrgof aShark 203 Fia. PAGE 132. A Fisliing Fleet 206 133. Male Salmon 207 134. Salmon-fishing 208 135. Female Salmon after Spawning 209 136. The Frog 211 137. Frogs' Eggs 211 138. From a Tadpole to a Frog 212 139. Skeleton of Frog 214 140. Toads' Eggs 215 141. Skeleton of the Tortoise (plastron removed). ... 218 142. Box-tortoise 218 143. Circulation in Reptiles .. . 219 144. Green Turtle 221 145. Hawk's-bill Turtle 222 146. Skull of Boa-constrictor. . 224 147. Poison Apparatus of the Rattlesnake 225 148. Rattlesnake 227 149. Cobra de Capello 229 150. Lizard 231 151. The Chameleon 232 152. The Iguana 233 153. The Horned Toad 234 154. Crocodile-hunting 236 156. Mouth of the Crocodile. . 237 156. Alligator 238 157. Just Hatched 239 158. Footprints of Labyriu- thodon 240 159. " The North Wind." 244 160. Skeleton of a Vulture. . . 245 161. Bones of a Wing 246 162. Leg of a Bird perching. . 247 163. Digestive Organs of a Fowl 248 164. Plan of Circulation in Birds and Mammals . . . 249 165. Parts of a Feather 251 166. Section of a Hen's Egg before Incubation 254 167. Building the Nest 265 xu ILLUSTRATION'S. FIG. PAGE FIG. 168. Nest of the Tailor-bird... 257 210. 169. Nest of the Weaver-bird . 258 211. 170. WildDucl3 186. Hunting the Ostrich 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. vm 299 300 ?,36 204. Trogon Elegans 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 Hornbill feed 241. ing its Mate 308 242. PAGE Bird-of-paradise 309 Plny-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 anil Beak of Bird of Prey 321 The Golden Eagle 321 Eagle's Nest 322 Tlie 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 Tiircupine 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 , Whiile, with its Young Calf 345 . Greenland Whale 347 . Whalebone 348 . Sperm-whale 349 . Dolphins 350 . The Narwhal 351 ILLUSTRATIONS. XIU FIG. PAGE 248. Horses 353 244. Group of Horses 356 245. Zebras 357 246. Stag, or Red-deer 359 247. Stomach of a Ruminating Animal 860 248. Reindeer digging in Snow 361 249. Travelling in Lapland... 362 250. Antelope 863 251. The Koodoo 864 252. The Gazelle 365 253. The Graceful Chamois. . . 366 254. Camel 368 255. Skeleton of a Camel 869 256. Bactrian Camel 370 257. The Llama 371 258. African Elephants 373 259. Indian Elephants 374 260. Lions 377 261. Foot of a Lion 878 FIG. PIGB 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 889 269. 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 IN THE SEA AND ON THE LAND. I. SPONGES. SUB-KDfGDOM, PKOTOZOA : CLASS, KHIZOPODA. 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. For a long time naturalists 2 ;. 1. — Sponge. ANIMAL LIFE IN THE SEA AND ON THE LAND. were uncertain about the matter, but it is now settled that thej' 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 Porms of Animals. — Upon nam- ing the wiird " animal," a picture comes be- fore (jur minds of some creature having a mouth to eat with, and eyes to see with, and possessing feet or wings, or some other moans of moving about ; but the sjionges 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 «])Ou~(s consist ol h11\ 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 Kg.3._G«ouPs o. 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. ns 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. — CiROiTLATioN 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- m& 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- SPONGEa 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 Bat. — 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 Glotb. 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. 10. 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. Fig. 1. — Venus's Flowee-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 sfjonges 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 ofE the rocks with forked instruments, and consequently they are often torn. 14. Method of Culture. — The demand for sponges has 10 ANIMAL LIFE IN THE SEA AND ON THE LAND. ■V* 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- loiger, 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 rip;. 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. \1. 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. HYDKOIDS. SOME ODD DELATIONS OF THE JELLY-FISHES. SUB-KINGDOM, CCBLENTBRATA : CLASS, HTDROZOA. 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 10, — 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 LAISfO. 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 Pig. 11 you will see a spray of hydroid magni- fied which shows two sjDore-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 with 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 which 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 Spore- 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. DiflFerence 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-tish. 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 Aukita), with Young in Vakiods 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. 17 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. III. JELLY-FISHES. SUB-KINGDOM, CCELENTKEATA : CLASS, HTDROZOA. 1. Jelly-flshes. — Wlien 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, lielpless 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. — Skction or Jel- ly-fish, SHOwiNU Tubes AND Mouth. JELLY-FISHES. 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 hydrdids. 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 oat 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 Fig. 14. — Jklly-fish (Cyancea Enplooamia) 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 clay. They arc 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 ])ower 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. v. How Jelly-fishes secure Pood. — The tentacles of jelly- lishes are covered with a great many lasso-cells. These Fig. 15. — Lasso-cells from A Fresh -WATER Hydroid (Maunified). a, Barbed Dart withiu the cell ; 6, Barbed Dart escaped from the cell ; c, Lasso fully ex- tended, carrying the dart at the end. JELLY-FISHES. 21 lasso -cells are too small to be seen without a micro- scope ; still, tliey 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 pai'alyze 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 Pig. 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 h 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— MedussB. — 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 m scientific books, is " Me- duste." 11. Size.-^Jj&Hy -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 will 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." 1.3. Color. — It would be impossible to describe the va- ried colors of jelly - fishes, as they include almost every hue, the beautiful tints being jjrobably 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 transpai'ent that as it floats upon the water we can scarce- JELLY-FISHES. 23 Ij' see the sub stanceof \\ hall -' '" it ih composed The 01.1 J paitsthat stiike the C} e aie the ciuiilai tiihe aiouiid the edge auel the foui la 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 Fig. 16. — MnsHROOMS of the Sea. 24 ANIMAL LIFE IN THE SEA AND ON THK 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 diflferent 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- F'g, 17. — Grocp of Phosphorescent Animals. cence. Aj it may be seen at any time of the year illu- rniriotni.^ 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. 17 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. IT- THE "PORTUGUESE MAN-OF-WAR." SUB-KIKGDOM, CCKLENTERATA : CLASS, HTDKOZOA. 1. Some one has 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 Avill 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 delieate beauty cannot be preserved, it will still be interesting to those who have never seen living ones. 28 ANIMAL LIFE IN THE SEA AXD ON THE LAND. i,!"*-" %f:^'\ 8 In watch- in o the "Por- tuguese Man- (it - ^\ ar " you ^^ ill 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 l)e extended to their full lenii'th, 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 lieen fancifully called fleets. Travellers occasionally speak of meeting great numbers of them, both large and small, stud- ding the surface of the ocean: probably th^ young ones were out sailing with their paventsr Fi-. IS- Tor.TUGCESE Man-of-war.' SEA-AME MONKS. 29 V. SEA-ANEMONES. SUB-KINGDOM, CCELENTEKATA : 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 rooks, 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 Fig. 19. — Stomach and Cha.mbers of Sea- A.NEMOXE. c, tentacles; d, month; e, stomach; o\g\ openiugs in the partitions ; k, chambers. SEA- ANEMONES. 81 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 IX 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 Fig, 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 our 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. 4 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. IV. 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, CCBLENTERATA : 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, bow- 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 natui-al 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 s]ieletons 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 lining 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 immediateljr 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 Fig. 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 Pieqe 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. COEALS. 39 to bud from the sides. The buds will grow into branches, throwing out other buds, somewhat as plants do, until we 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.EA Pallida (Natural size). 7. One Generation after Another. — As in other families one generation j)asses 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 tbey 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 Fig. 25. — Organ-pipe Coeal. 42 ANIMAL LIFE IN THE SEA AND ON THE LAND. branch 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 Fig. 26, — Fragment of 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 BEEFS. . 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 water 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 Eeefs? — 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 aljo\'e them. There may be only about an inch of living coral on the outside of the reef. Fig. 27. a, li, Surface of tlie Water; , Natural Bed of the Oceau ; d, Lagoon. I Coral Formation ; 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. 21. 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. 7. The Sea not too Eough 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 liirds. 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 ]iass the perils at its entrance. In Fig. 28 is a pretty little coral island with ships in its lagoon. If a CORAL beefs; 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- building corals do not thrive at a greater depth than one hundred and twenty or one hundred and eighty feet. .iiU., - Fi" 'J 8. — An Atoll 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, \vu 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 hel2:>less 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. CTENOPHORA. 49 vin. CTENOPHORA. JiAINTY MORSELS FOR THE WHALES. SUB-KINGDOM, OCELENTEKATA : 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 will 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- f':!]s will have to be raised before the search is successful. 5 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 Fig. 29. — Ctknophora. 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. CTENOFHOKA. 51 5. The Soft Bodies. — The soft bodies of the otenophora 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. 7. Food. — Although the otenophora 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 Otenophora 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, which wave rapidly in the water, 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 when these impatient cilia are striking the water ? They send the little thing round and round, darting up and 52 ANIMAL LIFE IN THE SEA AND ON THE LAND. down, till Wf Avonder which way it will go next. The cilia are worked by muscles under the control of the ani- mal, and are to the etenophora M'hat oars are to a ro-w- 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 Hash of rainbow colors. In fact, the cilia are so important and characteristic a feature of Fig. 30. — Cilia o.s the (Jills of a Ml'sskl. the etenophora that we should do well to become per- fectly familiar with them. The a])pearance 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 ma}^ 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 ver}^ closely we might think the gills consisted of only one piece. The plates are pulled apart in the drawing to show the cilia more distinctlv. 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 gro^v 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 oj)en, 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 fieculiar 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. 3L— Ctenophora and Phosphorescent Fiskes. 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. 1.3. Phosphorescence.— All the ctenophora are phospho- rescent. They are abundant on our own coasts, and are CTENOPHORA. 55 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 sjDarkle. 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 Pig. 32. This was 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. Fig. 32. — Pleurobrachia. 56 AXIMAL LIFE IN THE SEA AND ON THE LAND. IX. STAR-FISIIES. SUB-KINGDOM, ECHINODEnMATA ; 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 wliere tlie crevices between the stones afford good liiding-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 stai'-fishcs 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 inirple. 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 drj' 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. — Undkr Side of Rat, showing; the Hollow Tubes and the Limestone Plates of thk 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 brea,k 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. 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 tlie ani- fli^^f — —— Ba-=,^;?»- — — - — — ~_jdHP »5^-, ^gg^f. ^M Bp ^^^^H ^ f^ 1 f^^ - ^jS^^S^m te ^^^ ^1 ^p .^kI^B^^^^ ^ hH 9 WA P\^ 1 ^ 1 B v^ ^^ - ^yjji H ^■il B mf ^i^^s 1 H 1 ^^^^■k F i'^ BB j^m 1 1 1 ■i ^^H 1 p 1 W^^ ^j^fjh S ^y I JlHIhb,. ^id^^H^- ^^ .^A B Fig. 34. — Stae-pishes (Lowei; One showi.ng Usder Side and Tube-feet). mal is alive we may see between tliese spines tiny forks, with two j^rongs that are constantly snapping. The use of the forks is not perfectly understood ; they some- STAR-FISHES. 59 times catch small pre}', 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 Fig. 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 tnrn 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 liends its rays into a cup shape to holil 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 liel]i 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 ne.xt 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, ^^■hich squirm and grope around like a multitude of worms. As these are the or- gans by which star-fishes move, they are called tube-feet. They are lengthened and enlarged, much as the tentacles f)f 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 bv 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 exjielling the water, the body is dragged forward. Fig. 36 shows the interior of one of the rays. The tube-feet, g, are slinmken up quite short, STAR-FISHES. 61 which makes the water-bags, A, all the larger. Notice the mouth, «, the stomach, b, and the intestine, c. Fig. 3B. — Interior of 1{ay. u, month; &, stomach; c, intesliiie; d, upper surface; e, limss^une plates; /, ovary ; g, tube-feet ; A, water-bags. 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-sjieck. 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 AKlJ ON THE LAND. causes him to lose large quantities of his valuable prop- erty. It is estimateil that the damage every year to the oyster-beds between Staten Island and t'upc Cod amounts to 1^100,000. 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 ])art of summer or early in the fall, and are much dreaded by the owners of oyster-beds. ]'2. Some Uses of the Star-fish. — The oysterman has learned the value of these destructive jjcsts 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 soiTs 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 tlian our common ones which we have been studying. ■ SEA-URCHINS. 63 X. SEA-URCHINS. STJB-KreGDOM, ECIIINODER.\rATA : CLASS, ECIIINOIDEA. 1. Sea-urchins. — Wluit funny, prickly crcntures the sea- ui'cliiiis arc ,.,. I A person might easily mistake them for green chestnnt-hnrs scattered mi tlie beacji, and, lilancincr up hastily, lie might aliiiust expect to find the overhanging '■'^^mm Fig. SI. — Under Surface of a Sea - urchin, showing Rows of Scokers AMONG THE SPINKS. 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 AInD 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. Wc might almost say that the sea- urchin (Fig, 31) 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. Shkllok a ■SEA-n;^IIl^ 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 ends of the rays meet. 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 6 ^''J.. Sy. — Section of a Sk,4.-drchin. a, mouth; c, stomach; d, iutestiue; o, nuus; V, heart; /, mrtdreporic body; g, maiu water- tube ; p, tube-feet ; z, spines. 66 AXIMAL 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/J and the tube, g, cai-ries water to supply the tube-feet and their little water-bags, which are shown at jO. 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 urcliins never east oft' 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 ajaart. "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 sjjines 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 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 heak 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. Fig. 40. — Spine of Ska- urchin, MAGNIFIED, a, cross sectiou. 68 ANIMAL LIFE IN THE SEA AND ON THE LAND. r I \ K '% Fi