ORDER CHAM PS I A. 



FAMILY CROCODILIA. CROCODILE. 



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All the individuals composing this genus are covered with scales, more 

 or less varied in colour and number, according to the different species ; 

 their feet are flat and webbed, and are thus adapted to serve the purpose of 

 oars. 



CHELYS. This genus is distinguished from the Emydes by the characters 

 given above, and by the absence of the horny beak which characterise the 

 Testudina. 



The Matamata (Plate 1) is a native of Cayenne; where it frequents 

 lakes and rivers, preying upon water-fowl, fishes, and insects. Its flesh is 

 eaten by the natives as a delicacy. The carapace is depressed, with a keel 

 down the centre, and a furrow on each side of it; the snout is flexible, 

 forming a double tube ; a horny lamina? defends the jaws ; two rows of 

 cutaneous fringes run along the back of the neck ; an ear-like membranous 

 prolongation extends forward on the sides of the head ; four membranous 

 fringes hang from the throat, and two from the chin. The length of the 

 full-grown animal is about three feet. 



TRIONYX. The genera Trionyx and Chelonia are those alone of the 

 Chelonian order which have the ribs, although consolidated in the back- 

 plate, distinctly visible by their elevation on the inside of the shell, and by 

 their free projection beyond it ; they are distinguished, however, by the 

 absence in Trionyx of the bony belt which forms the disc of Chelonia ; 

 hence the skin, which extends some distance beyond the points of the ribs, 

 is flexible, and capable of being acted on by muscular radiations which pass 

 into it, for which purpose it is not covered with scales, but the whole 

 surface is enveloped in an epidermal tissue, which does not offer such oppo- 

 sition to motion as scales would. By raising or depressing, either separately 

 or together, these loose folds of extended skin, the animal is enabled to 

 swim with great swiftness, and in a very peculiar manner, rolling itself over 

 and over, so that, when moving upon the surface of the water, its back and 

 belly are alternately seen. They prey on fish, frogs, and even young 

 aquatic birds. 



The Nilotic Trionyx, or Soft Tortoise (the T. ^Egyptiacus of Geoffrey), is 

 three feet in length ; back-plate somewhat convex, and rather prominent 

 along the ridge of the spine ; ribs occupying a fourth part of the space 

 beyond the bony support ; front of the soft part of the back-plate slightly 

 festooned and not tubercular; the other part of the skin leathery, striated, 

 and rough ; its colour green, and spotted with white ; breast-plate having 

 its two anterior appendices very widely separated ; it has also four callo- 

 sities ; legs short and webbed. It is found in the Nile, though not very 

 common, where it is called Tyrse, and feeds upon the young crocodiles so 

 soon as they have burst their shell. 



Skeleton of Tortoise. 



k I 



a, clavicle ; b, scapula ; c, femur ; d, cervical vertebra; ; e, fibula ; /, caracoid bone ; 

 ij, dorsal vertebra; ; h, ribs ; t, sternal ribs ; k, pelvis ; /, tibia. 



ORDER II. CHAMPSIA. CROCODILES. 



THE Crocodiles had been included in the great genus Lacerta, till Cuvier 

 separated and formed them into a distinct genus under the name Crocoddus, 

 the characters of which are : tail flat on the sides ; hind feet entirely or 

 partially webbed ; tongue attached to the bottom of the mouth and not 

 extensible ; teeth numerous, pointed, and single ; body covered above with 

 strong hard scales, and below with soft broad scales ; the eyes protected 

 with three eyelids. Cuvier has also divided them into three subgenera, 

 Gavicds, Crocodiles, and Alligators. 



Family CROCODILE ; Crocodilia. 



ILLUSTRATIVE EXAMPLES. 

 PLATE 2. 



Genera. 



Ramphastoma - 



Crocodilus - - 



Champsa - - 



Species. 



- Gangeticus 



- Vulgaris - 



- Sclerops - 



Common Name. 



- Indian Gavial or Crocodile. 



- Nilotic Crocodile. 



- Spectacle Alligator. 



CHARACTERS OF THE GENERA. 



1. RAMPHASTOMA, or GAVIALS. Snout slender, very long, and rather 

 larger at the tip ; teeth almost of equal size, the fourth lower tooth on each 

 side received into a notch or groove in the upper jaw ; the hind feet 

 webbed to the tips of the toes, and notched on their outer edge ; two 

 small holes in the skull behind the eyes. 



2. CROCODILES (Proper). Head oblong and flattened ; teeth unequal, 

 the fourth on either side below received into notches, but not into holes in 

 the upper jaw ; in other respects like the Gavicds. 



3. CHAMPSA Alligator. Snout broad and obtuse ; teeth unequal, of 

 which the fourth on either side in the lower jaw enters into a hole in the 

 upper, but not a notch; the feet are only half-webbed, and not den- 

 ticulated. 



CHAMPSA. DESCRIPTION OF THE SPECIES. 



Crocodiles are both the largest and most powerful of the Saurous 

 reptiles ; their body is better protected with scales, and the skin of the 

 back especially, is so well guarded by numerous horny shields as to resist a 

 musket-ball : from it the negroes are in the habit of making helmets. The 

 scales on the back form a middle longitudinal crest, extending through its 

 whole length, and the tail has the crest deeply denticulated, and double at 

 its root ; the anterior extremities have five, and the posterior four toes, of 

 which the three inner only are provided with nails or claws, but all are 

 more or less webbed ; the eyes are placed near each other on the top of the 

 head and above the face, are very moveable, and protected by a nictitating 

 membrane or haw, besides the eyelids ; the tongue is short and thick, but 

 cannot be protruded from the mouth, which led the ancients to imagine 

 that it was wanting ; the body itself is of a pyramidal form and tapering, 

 covered above with four or six rows of square tubercular scales, and below 

 with smooth, soft, transverse, broad, horny bands, or scuta. They lay 

 from thirty to sixty eggs, at two or three different periods, which they bury 

 in the sand, and leave to be hatched by the sun ; to these the Ichneumon is 

 a very great enemy, and the great increase of crocodiles is only kept down 

 by the havoc which this animal makes amongst the eggs; and hence, 

 perhaps, have originated the divine honours which were paid to it by the 

 ancient Egyptians. 



The Indian Crocodile (Plate 2) is a native of the Ganges, and probably 

 of the neighbouring rivers, but is not considered to be dangerous to man, 

 living only on fish. Its head is very broad behind ; orbits very wide, and 

 much separated from each other ; the cranial holes large ; twenty-five teeth 

 on either side above, and twenty-eight below ; length of snout about an 

 eighth of that of the body ; two little scales only behind the head, followed 

 by four placed transversely, which are continued to those of the back. 



The Nilotic, or Common Crocodile (C. Vulgaris), is the largest animal of 

 the genus, measuring about thirty feet in length. It inhabits the Nile and 

 Senegal, and probably the other rivers of Africa ; but at present it is found 



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