W 3 THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BY PROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID THE HISTORY OF BIRDS; THEIR VARIETIES AND ODDITIES: COMPRISING QRAPHIC DESCRIPTIONS OF Nearly ail Known Species of Birds, with Fishes and Insects, the World over, and Illustrating their Vaned Habits, Modes of Life, and Distinguishing Pecu- liarities by Means of Delightful Anecdotes and Spirited Engravings. Prepared after Laborious Personal Research ; with the Aid of the Great Works of Cuvier, Buffon, Wood, Dallas, ETuttall, Bonaparte, Agazzis, Jardine, Brewer, and many others ; BY REV. W. SINGLE Y, A.M. OVER BOO SPIRITED ILLUSTRATIONS. PHILADELPHIA : EDGEWOOD PUBLISHING CO. COPYRIGHTED, ACCORDING TO ACT OF CONGRESS. CONTENTS. PAGE ON THE STUDY OF NATURE 13 BIRDS '. 27 PIES 78 PASSERINE BIRDS 143 GALLINACEOUS BIRDS 245 WADERS . 303 SWIMMERS 357 FISHES 411 APODAL FISH 411 JUGULAR FISH 418 THORACIC " 421 ABDOMINAL " 435 CHONDROPTERYGIOUS FISH 456 INSECTS 471 COLEOPTEROUS INSECTS 471 HEMIPTEROUS " 491 LEPIDOPTEROUS " 502 NEUROPTEROUS " * 511 HYMENOPTEROUS " ., 514 DIPTEROUS " ....* 530 APTEROUS * v 535 (5) JVJ36S7P6 INDEX OF SUBJECTS. A. PAGE Adjutant 316 Albatross 389 Amazon Ant 513 Anchovy 450 Angler 467 Ant Eater 513 Ants 513 Aphides 519 Aphis 500 Apteryx 300 Au)ss, 380 Avocet 346 B. Barbel 468 Bedbugs 534 Bees 522 Beetles 471 Bird of Paradise 118 Bittern 317 Blackbird 152* Blennies 469 Bluebird 197 Boat-bill..... 314 Bob-o-link 154 Booby 398 Bombardier 487 Borers 478 Bugs 498 Bullfinch 166 Bull-comber 471 Bunting ; 167 Bustards 286 Butterfly 503 Buzzard 36 C. Canary-finch 173 Carabus 487 Carp 451 Carrion Crow 103 Cassowary 298 Cat-bird 195 Cedar or Cherry Bird 210 Centipedes .' 558 Cerambyx or Capricorn 484 Chactodon . 426 Chafiinch 143 Chaja 308 Chatterer 211 Cheese-mite 469 Chick-a-dee 209 Chigoe 540 Chub 452 Cicadae 496 Coal Tit 208 Cochin-china 264 Cochineal 501 Coccinella 482 (7) INDEX OF SUBJECTS. PAGE Cock 258 Cockatoos 92 Cock-chafer 472 Cockroach 491 Codfish 418 Condor 28 Coot 352 Corn-weevil 483 Corvorant 395 Crab 549 Crane ! 303 Crane-fly 530 Craw-fish 557 Creeper 135 Cricket 493 Cross-bill 161 Crow-blackbird 156 Crows 99 Cuckoo 121 Curculio 483 Curlew 319 Cynips 504 D. Dabchick 354 Dace 453 Darter 402 Day-fly 511 Dermestes 478 Devil-fish 468 Divers 404 Dodo 301, 302 Dog-fish 462 Doree 422 Dorking Fowl 265 Dotterel 334 Dragon-fly 511 Ducks 357 Dunlin 330 E. PAQE Eagle 38-50 Earwig 489 Eel 411 Eider Duck 364 Emu 300 Esculent Swallow 220 F. Falcon 38 Fieldfare 99 Finch 169 Flamingo 361 Flatfish 423 Flea 539 Flounder 426 Fly 511-531 Flying-fish 443 Fly-catcher 176 Fowls 258 G. Gad-fly 460 Gadwall or Grey 370 Gall-insect 514 Gallinule 341 Gannet 396 Garganey 369 Gentil Falcon 59 Glow-worm 485 Gnat 533 Goat-sucker 74 Godwit 322 Goldfinch 172 Goldfish ,. 454 Goosander 366 Goose 360 Goshawk 60 Grayling 440 INDEX OF SUBJECTS. PAGE Grebe, or daunt 352 Greenfinch 163 Grouse 273 Grosbeaks 161 Gudgeon .' 452 Guinea Fowl 272 Guillemot 389 Gulls .: 406 Gurnard 434 Gynmotus 413 H. Haddock 419 Hake-fish 420 Hawk 63 Hawkmoth 506 Hedge Accentor, or Sparrow. ... 1 95 Hen Harrier 60 Heron 303-310 Herring 445 Holibut 425 Hoopoe 223 Hornbill 97 Hornet 517 Humming Bird 137 I. Ibis 345 J. Jackdaw 108 Jager, Richardson' s 408 Jay 109 K. King Bird 176 Kingfisher 132 Kinglet, Fiery-Crowned 1 96 Kite 59 Lady-bug 482 Lamprey 466 Lark , 144 Lasher 469 Ling 420 Linnet 169 Loach 468 Lobster 552 Locust 492 Locust-eating Thrush 160 Loon 405 Louse 538 Lucanus 476 Lumpsucker 470 Lyre-bird 225 Lytta 48$ M. Macaw 90 Mackerel 429 Magpie Ill Mantis 491 May-fly 510 ! Megapode 252^ Merganser, hooded 410 Missel, or Misseltoe Thrush 15G Mocking-bird 157 Monk-fish 462 Moths 506 Mullet 441 Musk 374 Musquito s 534 10 INDEX OF SUBJECTS. N. PAGE Nightingale , . 187 Nut-hatch .131 O. Oriole 113 Osprey . 53 Ostrich 292 Ouzel, water 145 Oven bird 117 Owls 66-74 Ox-bird, or Dunlin 330 P. Papuan Podargus 75 Parrots 81 Partridge 280 Peacock 250 Pelicans 391 Penguins 384 Perch 428 Peregrine Falcon 64 Peristera 238 Petrel 385 Phalarope 356 Phasianella 240 Pheasant 253 Pigeons 226 Pike 440 Pill-chafer 475 Pilchard 448 Pintado Tribe 271 Pipit, meadow 184 Plaise 423-426 Plant-lice 499 Plovers 333 Porcupine, sea 470 Prawn 554 Ptarmigan 279 Ptinus 478 Purre 324 Q. Qua-bird 312 Quail 284 R. Rail 338 Rapacious birds 27 Raven 101 Ray 464 Red-breast 191 Redstart 148 American 178 Remora 421 Rice-bird 1 54 Ring-dove 229 Roach 453 Robin 192 Rock-dove 243 Rook 105 Rose-chafer 474 Ruff, or Reeve 329 S. Salmon 435 Sawfly 514 Sandpiper 328 Wilson's 331 Sand-wasp 516 Scarabseus 471 Scorpion 548 Sea-horse 467 Shad 449 Shark 457-462 INDEX OF SUBJECTS. 11 Shrike, great or cinereous 78 Shrimp 554 Silkworm 507 Silurus 469 Siskin 195 Skate 465 Skimmer 409 Skippers 486 Smelt 439 Snipe 3!9 Spanish-fly 488 Sparrow 1 70 Sparrow-hawk 62 Spheges 516 Spiders 542 Spider-fly 534 Spoonbill 348 Sprat 449 Stag-beetle 476 Starling 143 Stilt 334 Stork 304 Sturgeon 456 Sucking-fish 421 Surmullets 433 Swallows c 212 Swan 357 Sword-fish : 416 Sylphse 480 T. Tailor-bird 203 Talpicoti 237 Tarantula 548 Tatler 348 Teal 373 Tench 452 Termes 535 Tern 409 PAGE Thornback 466 Thoracic Fish 421 Thrush 150 Thunny Fish 43 1 Tick 541 Titmice 204 Torpedo 464 Toucan 93 Trogon 223 Trout 437 Trumpeter 290 Turbot 423 Turkey 245-252 Turnstone 330 U. Umber 440 V. Vinago 244 Vireo, red-eyed ] 80 Vultures 31-36 W. Wagtail 189 Warbler, garden 1 49 Warblers 1 93 Wasp 517 Waxwing, or chatterer 211 Weevil 433 Whame-fly 532 Wheat-ear 148 Whidah 167 12 INDEX OF SUBJECTS. Whip-poor-will 75 Whiting 419 Widgeon 371 Wolf-fish . .413 PAGE Woodcock 323 Wood-pecker 128 Wren 193 Wryneck 130 ON THE STUDY OF NATURE. There is no division of the animal world in which we are more led to admire th wisdom of the Supreme Being, than in the different feathered tribes. Their struc- ture and habits of life are wonderfully fitted for the various functions they have to perform. Their bodies are clad with feathers, which form an envelope much lighter than hair. These lie over each other close to the body, like the tiles of a house ; and are arranged from the fore-part backward, by which means the animals are enabled the more conveniently to cut their way through the air. For this purpose also the head is small and the bill somewhat wedge-shaped ; the neck is long, and easily movable in all directions ; and the body slender, sharp on the under side, and flat or round on the back. The bones likewise are hollow, and very light compara- tively with those of terrestrial animals. For the purpose of giving warmth to th body, a short and soft down fills up all the vacant spaces between the shafts of tho feathers. Birds are enabled to rise into and move from place to place in the air, by meanii of the members that are denominated wings. The muscles by which the wings ar move are exceedingly large ; and have been estimated, in some instances, to consti- tute not less than a sixth part of the weight of the whole body. When a bird is on the ground, and intends to fly, he takes a leap, stretches his wings from the body, and strikes them downward with great force. By this stroke the body is thrown into an oblique position. That part o fthe force which tended upward is destroyed by the weight of the bird ; and the horizontal force serves to carry him forward. The stroke being completed, he moves up his wings. These being contracted, and having their edges turned upward, meet with little resistance from the air. When they are sufficiently elevated, the bird makes a second stroke downward, and the impulse of the air again moves him forward. These successive strokes act as so many leaps taken in air. When the bird wants to turn to the right or left, he strikes strongly with the opposite wing, and this impels him to the proper side. The tail acts like the rudder of a ship ; except that it moves him upward or downward, instead of sideways. If the bird wants to rise, he raises his tail ; and if to fall, he depresses it ; whilst he is in an horizontal position, it keeps him steady. A bird, by spreading his wings, can continue to move horizontally in the air for some time, without striking them ; because he has acquired a sufficient velocity, and his wings, being parallel to the horizon, meet with but little resistance. When he begins to fall, he can easily steer himself upward by his tail, till the motion he had acquired is nearly spent ; he must then renew it by two or three more strokes of his wings. On alighting, he expands his wings and tail full against the air, that they may meet with all the resistance possible. The centre of gravity in birds is somewhat behind the wings ; and, to counterbal- ance this, most of them maybe observed to thrust out their head and neck in flying. This is very apparent in the flight of Ducks, Geese, and several other species of water-fowl, whose centre of gravity is further backward than in the land birds. In the Heron, on the contrary, whose long head and neck, although folded up in flight, overbalance the rest of the bodv, the long legs are extended, in order to give the proper counterpoise, and to supply what is wanting from the shortness of the tail. The feathers of birds would perpetually imbibe the moisture of the atmosphere ; and, during rain, would absorb so much wet, as to impede their flight, had not the wisdom of Providence obviated this inconvenience by a most effectual expedient. They are each furnished on the rump with two glands, in which a quantity of unctu- ous matter is constantly secreting. This is occasionally pressed out by the bill, aj d used for the lubrication of the feathers. The birds that share, as it were, the hal i- tations of man, and live principally under cover, do not require so great a supply, and therefore are not provided with so large a stock of this fluid, as thosje that rove abroad, and reside in the open element. It is on this account that poultry, when wet, make the ruffled and uncomfortable appearance that we observe. (13) 14 FUNCTIONS OF BIRDS. As birds are continually passing among the hedges and thickets, their eyes are de- fended from injury by a membrane, which can at pleasure be drawn over the whole eye like a curtain. 'This is neither opaque nor wholly pellucid, but is somewhat transparent. In birds we find that the sight is much more piercing, extensive, and exact, than in the other orders of animals. The eye is large in proportion to the bulk of the head. This is a superiority conferred upon them not without a corres- ponding utility; it seems even indispensable to their safety and subsistence. "Were this organ dull, or were it, in the least degree, opaque, the rapidity of their motion would expose them to the danger of striking against various objects in their flight. Jn this case their celerity, instead of being an advantage, would become an evil, and their flight would be restrained by the danger resulting from it. Indeed, we maj consider the velocity with which an animal moves, as a sure indication of the perfec- tion of its vision. Birds respire by means of air-vessels, that are extended through their whole body, and adhere to the under surface of the bones. These, by their motion, force the ait through the true lungs, which are very small, seated in the uppermost part of the chest, and closely braced down to the back and ribs. The use of this general diffu- sion of air through the bodies of birds, is to prevent their respiration from being stopped or interrupted by the rapidity of their motion through a resisting medium. The resistance of the air increases in proportion to the celerity of the motion ; and were it possible for a man to move with swiftness equal to that of a Swallow, the resistance of the air, as he is not furnished with reservoirs similar to those of birds, would soon suffocate him. Some species of birds are confined to particular countries ; others are widely dis- persed ; and several change their abode at certain seasons of the year, and migrate to climates better suited to their temperament or mode of life than those which they leave. Many of our own birds, directed by a peculiar and unerring instinct, retire, before the commencement of the cold season, to the southern districts, and again return in the spring. The causes usually assigned for migration are, either a defect of food, or the want of a secure and proper asylum for incubation, and the nutrition of their offspring. It appears from very accurate observations, founded on numerous experiments, that the peculiar notes, or sony, of the different species of Birds, are acquired, and are no more innate than language is in man. The attempt of a nestling bird to sing, may be compared with the imperfect endeavor of a child to talk. The first essay seems not to possess the slightest rudiments of the future song ; but, as the bird grows older, and stronger, it is not difficult to perceive what he is attempting. Whilst the scholar is thus endeavoring to form his song, when, he is once sure of a passage, he commonly raises his tone ; but when unable to execute the passage, he drops it. What the nestling is thus not thoroughly master of, he hurries over; lowering his tone, as if he did not wish to be heard, and as if he could not yet satisfy himself. A common Sparrow, taken from the nest when very young, and placed near a Linnet and Goldfinch, adopted a song that was a mixture of the notes of these- two. Three nestling Linnets were educated, one under a Sky-lark, another under a Wood-lark, and the third under a Tit-lark ; and, instead of the song peculiar to their own species, they adhered entirely to that of their respective instructors. A Linnet taken from the nest when about three days old, and brought up in the house of Mr Matthews, an apothecary, at Kensington, having no other sounds to imitate, almost articulated the words " pretty boy ;" and a few other short sentences. The owner ol ibis bird said, that it had neither the note nor the call of any bird whatever. It died in the year 1772. These, and other well-authenticated facts, tend to prove that Birds have no innate notes, but that, like mankind, the language they first learn after they come into the world, is generally that which they adopt in after life. It may, however, seem unac- countable, why, in a wild state, they adhere so steadily as they do to the song of their own species only, when the notes of so many others are to be heard around them. This evidently arises from the attention that is paid by the nestling bird to the instructions of its own parent only, and it is generally disregarding the notes of all the rest. Persons, however, who have an accurate ear, and have studied the notes of birds, can very often distinguish some that have a song mixed with the notes of other species. ITie food of birds is of course very different in the different kinds. Some are FUNCTIONS OF BIRDS. 15 altogether carnivorous ; others, as many of the web-footed tribes, live on fish ; eomo on insects and worms, and many on fruits or grain. The extraordinary powers of the gizzard in the graminivorous tribes, in comminuting their hard food, so as to pro- pare it for digestion, are such as almost to exceed credibility. In order to ascertain the strength of these stomachs, the Abbe Spallanzani made many cruel, though at the same time curious and not uninteresting experiments. Tin tubes full of grain were forced into the stomachs of Turkeys ; and, after remaining twenty hours, were found to be broken, compressed, and distorted in a most irregular manner. The stomach of a Cock, in the space of twenty-four hours, broke off the angles of a piece of rough, jagged glass ; and, on examining the gizzard, no wound or laceration appeared, Twelve strong tin needles were firmly fixed into a ball of lead, with their points projecting about a quarter of an inch from the surface ; thus armed, it was covered with a case of paper, and forced down the throat of a Turkey. The bird retained it a day and a half without exhibiting the least symptom of uneasiness. When the Turkey was killed, the points of nearly all the needles were found to be broken off close to the surface of the ball Twelve small lancets, very sharp both at the points and edges, were fixed in a similar ball of lead. These were given in the same manner, to a Turkey-cock, and left eight hours in the stomach ; at the expiration of which time that organ was opened, but nothing appeared except the naked ball ; the twelve lancets having been all broken to pieces. From these facts it was concluded, that the stbnes so often found in the stomachs of many of the feathered tribes, are highly useful in assisting the gastric juices to grind down the grain and other hard substances which constitute their food. The stones themselves, also, being ground down and separated by the powerful action of the gizzard, are mixed with the food, and no doubt contribute to the health as well as to the nutri- ment of the animals. All birds are oviparous, or produce eggs, from which, after the process of incuba- tion, the young are extruded. These eggs differ in the different species, in number, figure, and color. They contain the rudiments of the future offspring ; for the maturation and bringing to perfection of which, in the incubation, there is a bubble of air at the large end, betwixt the shell and the inside skin. It is supposed that, from the warmth communicated by the sitting bird to this confined air, its spring is in- creased beyond its natural tenor, and, afthe same time, its parts are put into motion by the gentle rarefaction. Hence pressure and motion are communicated to the parts of the egg ; and these, in some unknown manner, gradually promote the for- mation and growth of the young one, till the appointed time of its exclusion. The use of that part of the egg called the treddle, is not only to retain the different liquids in their proper places, but also to keep the same part of the yolk uppermost ; which it will effectually do, though the egg be turned nearly every way. The mechanism seems to be this : the treddle is specifically lighter than the white in which it swims ; and being connected with the membranes of the yolk, at a point somewhat out of the direction of its axis, this causes one side to become heavier than the other. Thus the yolk, being made buoyant in the midst of the white, is, by its own heavy side, kept with the same part always uppermost. The nests of birds are, in general, constructed with astonishing art ; and with a degree of architectural skill and propriety, that would foil all the boasted talents of man to imitate. 'Mark it well, within, without : No tool had he that wrought ; no knife to cut, No nail to fix, no bodkin to insert, No glue to join ; his little beak was all. And yet, how neatly finish'd ! What nice hand, With every implement and means of art, And twenty years' apprenticeship to boot, Could make me such another ? Fondly then We boast of excellence, whose noblest skill Instinctive genius foils. In most of the species both the male and female assist in this interesting operation. They each bring materials to the place : first sticks, moss, or straws, for the founda- tion and exterior : then hair, wool, or the down of animals or plants, to form a soft and commodious bed for the eggs, and for the bodies of their tender young, when batched. The outsides of the nests bear in general so great a resemblance in coloi 16 FUNCTIONS OF BIRDS. to the surrounding foliage or branches, as not easily to be discovered even by per eons who are in search of them. This is one of those numerous and wonderful contrivances which compel us to believe that every part of the creation is under the protection of a superintending Itetttg, whose goodness knows no bounds. Without this, what can we suppose it ia that instigates a creature which may never before have had young, to form a nest, hollow, for the purpose of containing eggs ; (things that as yet it knows nothing of ;) wid of concentrating a necessary proportion of heat for the incubation ? Without this, what can we suppose it is that dictates the necessity of forming the outside of this nest with coarse materials, as a foundation, and of lining its interior with more delicate substances ? How do these animals learn that they are to have eggs, and that these eggs will require a nest of a certain size and capacity? Who is it that teaches them to calculate the time with such exactness, that they never lay their eggs before the receptacle for them is finished ? No one can surely be so blind as to observe all this, and not to perceive the superintendence of a beneficent wisdom influencing every operation. The classification of birds is principally founded on their habits of life ; and on the formation of their external parts, particularly of their bills. The grand divisi is into LAND BIRDS and WATER BIROS. LAND BIRDS. 1. Rapacious Birds (accipitres], have their bill hooked ; and on each side of th upper mandible there is an angular projection. They consist of Vultures, Eagle* or Hawks, and Owls. These birds are all carnivorous, and associate in pairs; and the female is generally larger and stronger than the male. 2. Pies (piece). These have their bills sharp at the edge, compressed at the sides, and convex on the upper surface. The principal genera are Shrikes, Crows, Rollors, Orioles, Grackles, Humming-birds, Parrots, Toucans, Cuckoos, Woodpeckers, Horn- bills, and Kingfishers. Some of them associate in pairs, and others congregate. They live on various kinds of food ; and usually build their nests in trees, the mill* feeding the female during the process of incubation. 3. Passerine Birds (passeres), have a conical, sharp-pointed bill. To this order belong the Finches, Grosbeaks, Buntings, Thrushes, Fly-catchers, Swallows, Laiks, Wagtails, Titmice, and Pigeons. While breeding they live chiefly in pairs; and th nests of several of the species are of curious and singular construction. The greater number of them sing. Some of them subsist on seeds, and others on insects. 4. Gallinaceous Birds (yallinaz). The bills of these birds have the upper mandi ble considerably arched, Pheasants, Turkeys, Peacocks, Bustards, Pintadoes, and Grouse, all belong to this order. They live principally on the ground ; and scratch the earth with their feet for the purpose of finding grain and seeds. They usually associate in families, consisting of one male and several females. Their nests are artlessly formed on the ground ; and the females produce a numerous offspring WATER BIRDS. 5. Waders' (grattce ). These have a roundish bill, and a fleshy tongue ; and the legs of most of the species are long. The principal genera are the Herons, Plovers, Snipes, and Sandpipers, which live for the most part among marshes and fens, and feed on worms and other animal productions. They form nests on the ground. 6. Swimmers (anseres). The bills of these birds are broad at the top, and covered with a membranaceous skin. The tribes best known are the Ducks, Auks, Pen- guins, Petrels, Pelicans, Guillemots, Gulls, and Terns. They live chiefly in the water, and feed on fish, worms, and aquatic plants. Most of the species are poly* gamous, and construct their nests among reeds or in moist places. The females lay many eggs. FUNCTIONS OF FISHES. 17 FISHES. Were we acquainted with no other animals than those which inhabit the land, and breathe the air of our atmosphere, it would appear absurd to be told that any race of beings could exist only in the water : we should naturally conclude, from the effect produced on our own bodies when plunged into that element, that the powers of life could not there be sustained. But we find, from experience, that the very depths of the ocean are crowded with inhabitants, which, in their construction, modes of life, and general design, are as truly wonderful as those on the land. Their history, however, must always remain imperfect, since the element in which they live is beyond human access, and of such vast dimensions, as to throw by far the greater part of them altogether out of the reach of man. That they are in every respect, both of external and internal conformation, well adapted to their element and modes of life, we are not permitted to doubt. The body is, in general, slender, flattened at the sides, and always somewhat pointed at the head. This enables them, with ease, to cut through the resisting medium which they inhabit. Some of them are endowed with such extraordinary powers of pro- gressive motion, that they are able not only to overtake the fastest sailing vessels, but, during the swiftest course of these, to play round them without any apparently extraordinary efforts. Their bodies are in general covered with a kind of horny scales, to keep them from being injured by the pressure of the watei. Several of them are enveloped with a Cat and oily substance, to preserve them from putrefaction, and to guard them from extreme cold. They breathe by means of certain organs that are placed fa eack ide of the neck, and called gills. In this operation they fill their mouth with water, which they throw backward, with so much force as to lift open the great flap, and force it out behind. 'And in the passage of this water, among the feather-like pro- cesses of the gills, all, or at least the greatest part, of the air contained in it, is left behind, and carried into the body to perform its part in the animal economy. In proof of this fact, it has-been ascertained that, if the air be extracted from water into which fish are put, they immediately come to the surface nd gasp as. if for breath. Hence, distilled water is to fish what the vacuum formed by an air-pump is to most other animals. This is the reason why, in winter, when a fish-pond is en- tirely frozen over, it is necessary to break holes in the ice, not that the fish may come to feed, but that they may come to breathe. Without such precaution, if the pond be small, and the fish be numerous, they will die from the corruption of the water. Fisbefl Are nearly of the same specific gravity with water, and swim by means of their fins and tail. The muscular force of the latter is very great. Their direct motion is obtained by moving the tail from one side to the other, with a vibrating motion ; and, by strongly bending the tail sideways, this part of their body acts like the rudder of a ship, and enables them to move in an opposite direction. The tins of a fish keep it upright, especially the belly-fins, which act like feet ; without thesw it would float with its back downward, as the centre of gravity lies near the back. In addition to the fins and tail, the air-bladder is of material assistance to fish in swimming, as it is by means of this that they increase or diminish the specific gravity of their bodies. When, by their abdominal muscles, they compress the air contained in this bladder, the bulk of their body is diminished, their weight compared with that of the water, is increased, and they consequently sink. If they want to rise, they relax the pressure of the muscles, the air-bladder again acquires its natural size, the bo