277 



APTYCHUS. 



AQUATIC ANIMALS. 



278 



congeners of the Dinoi^nis are suffering in like manner. The Apteryx 

 is not however extinct, as many stuffed specimens exist in the 

 museums of England ; and, at the present moment (June, 1853), there 

 is a living specimen in the gardens of the Zoological Society, Regent's 

 Park. Of all birds at present known the Apteryx appears to have the 

 wings the most reduced to their simplest rudiments. Its general form 

 is that of the Penguin, and in size it is seldom quite so big as our 

 common goose. The beak is very long and slender, marked on 

 each side with a longitudinal groove, and covered with a membrane 

 at its base. It differs from other birds in the completeness of its 

 diaphragm, and in the absence of abdominal air-cells. The bones are 

 not hollow, as is mostly the case in birds ; the sternum is very small, 

 and the ribs are extraordinarily broad ; the feathers have no accessory 

 plume, and their shafts are prolonged beyond the back ; the feet have 

 a short and elevated hind-toe, of which the claw alone is externally 

 visible. 



The native name of this bird is Kiwi-Kiwi, given it on account of 

 its peculiar cry. It is a nocturnal bird, and preys on snails, insects, 

 and worms. Whilst at rest it has the singular habit of resting on the 

 tip of its bill, which is its most characteristic position. 



Apteryx (A. aiutralii). 



It runs with considerable rapidity, and when hunted by dogs it 

 makes a hole in the earth for the purpose of concealment, or it retires 

 into the natural cavities of the rocks. When attacked it defends itself 

 with considerable vigour. The natives hunt it for the sake of its skin, 

 which is used by the chiefs for their dresses, and on this account it is 

 highly valued. 



A'PTYCHUS (Von Meyer), one of the generic names of a singular 

 Fossil, supposed to be the remains of a Conchiferous Mollusk, or the 

 :ilar shell of a Cephalopod. Its other names are Trigontllitet, 

 Icldhyosiayonites, and Lepadita. The species belong to the Ammoni- 

 tit.nms strata, and specimens sometimes occur (as at Solenhofen) in 

 tin' !;nt chamber of the Ammonites. The structure is fibrous. 



AQUATIC ANIMALS. The element in which animals habitually 

 n Kiel.', or to which they occasionally resort for the purpose of pro- 

 curing food or seeking shelter, is so intimately connected with, and 

 bears .so obvious a relation to, not only their manners and economy, 

 but likewise their outward forma and internal structure, that it is not 

 Kin-prising that those wlio first turned their attention to the study of 

 zoology, and sought to introduce the principles of classification into 

 the animal kingdom, should have been so forcibly struck with its 

 inilM>rtance as to have made it the primary basis of their system. 

 " Animals," says Aristotle (' Hist.' b. i. c. 1), " may be distributed into 

 ditl'eivnt classes according to their manner of living, their actions, 



their character, and their parts Considered according to their 



i i ( living, their actions, and their character, they are divided 

 into terrestrial and aquatic. The aquatic are divided into two classes ; 

 IK-, n.s is the case with many fishes, pass their whole life in the 

 water, breathe that element, and find their food in it ; nor do they 

 li'ave it: the others obtain their food in the water, and even 

 h:i)>itiially reside in it, but they do not breathe it ; they breathe air, 

 :iiul bring forth their young on dry land. Among these latter some 

 lire' provided with feet and walk upon dry land, others have wings 

 mi'l fly, and others, like the water-serpent, have no feet. . . . . 

 Aquatic animals inhabit seas, lakes, marshes, and rivers." These 

 principles of classification, in which the habits of animals take prece- 

 ili'iins of those modifications in their organic conformation which 

 produce these very habits, have long since ceased to be adopted by 

 ilic naturalists; notwithstanding which there is perhaps no 

 inquiry which can engage the attention of the zoologist more fruitful 

 in ext n and interesting results than the c> moderation of 



tli" "rvalue structure of animals in relation to the clement in which 

 nature has ordained them to live. 



Those animals which reside entirely hi the water, and seek their 



food and nurture their young in that element, have their organisation, 

 even to the most minute circumstance, rigidly adapted to these pur- 

 poses. The extremities by which progressive motion is performed in 

 the acts of walking and flying would be a serious impediment to the 

 movements of animals residing in an element of the same specific 

 gravity as their own bodies : these organs accordingly are either 

 entirely wanting, or are reduced to mere rudiments, which serve 

 indeed to keep the body steady and preserve its equilibrium,- but are 

 entirely useless in assisting its progression. Such are the fins of fishes, 

 and the flippers, as they are called, of the Whale. The real organ of 

 progression in both cases is the body itself, which is prolonged and 

 attenuated towards the tail, compressed on the sides, and provided 

 with extremely powerful muscles, with which, by alternately striking 

 the water on either side, the animal propels itself forward with a force 

 and velocity unexampled in any other class of animated beings. It is 

 upon this principle that a boat is urged forward by means of a single 

 oar in the stern. The great majority of these animals not only reside 

 habitually in the water, and seek their food there, but likewise breathe 

 that element, and are consequently furnished with an appropriate 

 apparatus for extracting the oxygen gas from its general mass. These 

 tribes may reside at any depth of the ocean and for any length of 

 time ; they are not under the necessity of coming frequently to the 

 surface for the purpose of breathing, and their organisation is modified 

 accordingly. Instead of having the tail broad horizontally, it is broad 

 in a vertical direction, which enables them to turn with astonishing 

 rapidity, and is no impediment, but rather an assistant to their 

 forward movements. But the case is different in the Whales 

 and allied animals, which, though residing entirely in the water, 

 breathe air by means of lungs like ordinary Mammalia, and are 

 consequently obliged to come continually to the surface. For this 

 purpose they are provided with a powerful cartilaginous tail flattened 

 horizontally, by moving which upwards or downwards as the occasion 

 requires, they ascend to or descend from the greatest depths of 

 the ocean with almost incredible speed. Fishes, though capable of 

 proceeding straight forwards, or of turning with great rapidity, are 

 comparatively slow in changing their depths ; and if they breathed 

 air, they would frequently be suffocated before they could arrive at 

 the surface, from the vertical position of the tail not being adapted to 

 propel them in a vertical direction. But by a simple change, merely 

 by the direction of the tail being altered from the vertical to the 

 horizontal position, the object of nature is accomplished, and the air- 

 breathing Cetaceous Animals are adapted to all the circumstances of 

 an aquatic life. Another beautiful adaptation is observed in the 

 position of the mamma;, for the Cetacea, like warm-blooded quadru- 

 peds, suckle their young ; these are situated upon the breast, and 

 when the young animal requires to suck, the mother stands, as it 

 were, upright in the water, with her head and shoulders elevated 

 above the surface, supporting herself by means of her flippers, or 

 fore paws. In this position she is enabled to supply her cub with 

 the food which nature has provided, and which she could not have 

 accomplished had the mammae been placed in any other position. 



There is another extensive tribe of aquatic animals, which are 

 provided with perfect articulated members, sometimes indeed supplied 

 with fringes which convert them into a swimming apparatus, but 

 always adapted to enable the animals to walk or crawl along the 

 bottom. Such is the case with all the Crustaceous tribes the crabs, 

 lobsters, prawns, &c. ; and these animals, as is well known, can walk 

 on dry land with the same ease as at the bottom of the ocean. When 

 they swim, it is by means of the tail, which is always constructed for 

 that special purpose, and is large and powerful. 



Nor is the modification of structure less striking when we examine 

 those land-animals which breathe air, and resort only occasionally to 

 the water. As they are intermediate in habits, so are they likewise 

 intermediate in structure between these two extremes ; and the degree 

 in which their organisation is modified, when compared with either 

 of the two types, is exactly proportioned to the difference of their 

 habits and economy. All Mammals and Reptiles, for instance, which 

 seek their food in fresh-water rivers and lakes, partake more of 

 terrestrial than of aquatic habits. The extent of water with which 

 they are conversant is, in this case, very small when compared to 

 the extent of land, and their organisation differs but slightly from 

 that of ordinary land animals ; their extremities are perfectly developed, 

 and of the ordinary form, the principal difference being that their 

 toes are united by an expanded web or membrane, which gives the 

 paw a broad oar-like form, and thus converts it into a convenient 

 instrument of swimming, at the same time that it scarcely interferes 

 with the most perfect freedom of walking and running on land. Of 

 this nature are the extremities of all the vertebrated terrestrial 

 animals which seek their food in fresh water, the otters, beavers, &c. 

 among mammals; the whole order of Natatores, comprising the ducks, 

 swans, pelicans, gulls, auks, puffins, &c. among the birds; and the 



n liles, alligators, fresh-water tortoises, and frogs, among tho 



reptiles. All these animals are, properly speaking, web-footed, and 

 their aquatic habits are less prominent and powerful than their 

 terrestrial ; their organs of motion in fact are but little different from 

 those of common terrestrial animals. In those which frequent the 

 salt-water, on the contrary, the aquatic habits greatly predominate 

 over the terrestrial : they live less on land than in water and tho 



