SAURIA. 273 



the hind, of which the three inward only of each foot are furnished with claws, all of them being more 

 or less connected by membrane ; a single row of pointed teeth in each jaw ; the tongue flat and 

 fleshy, and attached very near to its edges, which led the ancients to believe that it was altogether 

 wanting ; the penis single ; the anal orifice longitudinal ; the back and tail covered with great square 

 scales of exceeding strength, having an elevated ridge along their middle ; and a deeply dentelated 

 crest upon the tail, double at its base. The scales of the belly are also square, but smooth and 

 narrow. The nostrils, opening at the tip of the muzzle by two small transverse fissures which close 

 as valves, are continued by a long straight canal pierced in the palate bones and sphenoid, as far as 

 the throat. 



The lower jaw is prolonged backward beyond the skull, which occasions the upper one to appear 

 moveable, as the ancients asserted to be the case: the latter can only move, however, with the 

 entire head. 



The external ear is closed at will by two fleshy lips ; and the eye has three lids. Under the throat 

 are two small holes, the orifices of glands, where a musky pommade is secreted. 



The vertebrae of the neck are propped together by little false ribs, which render lateral movement 

 difficult : hence these animals cannot readily change their course, and are easily avoided by turning. 

 They are the only Saurians which have no clavicular bones ; but their coracoid apophyses are attached 

 to the sternum, as in all the others. Besides the ordinary true and false ribs, their abdomen is pro- 

 tected by others, which do not ascend to the spine, and which appear to be produced by the ossifica- 

 tion of the tendinous extremities of the straight muscles. 



Their lungs do not penetrate into the abdomen, as in other Reptiles ; and the fleshy fibres adhering 

 to the portion of peritonaeum which invests the liver, impart the appearance of a diaphragm ; cir- 

 cumstances which, conjoined to the particular of their heart being divided into three chambers, 

 wherein the blood that conies from the lungs does not mingle so completely with that of the body as 

 in other Reptiles, ally these animals somewhat nearer to the warm-blooded quadrupeds. 



Their ear-drum and pterogoid apophyses are fixed to the skull, as in the Tortoises. 



Their eggs are hard, and the size of those of domestic Geese, whence the Crocodiles are reputed to 

 be, of all animals, those which attain the greatest dimensions considering their size at birth. The 

 females guard their eggs, and continue to protect the young for some months after exclusion. 



They inhabit fresh water, and are very carnivorous, but are unable to swallow under water ; and 

 their habit is to drown their prey, and then place it in some hole beneath the surface, where they 

 leave it to putrefy before they devour it. 



They differ, indeed, so much from other Lizards, that several recent authors have deemed it neces- 

 sary to make of them a particular order, termed Lnricata by Merrem and Fitzinger, and Emydosaura 

 by De Blainville. 



The species, more numerous than has hitherto been supposed, fall into three distinct subgenera. 



The Gavials, Cuv., — 

 Have the muzzle slender, and very much elongated ; the teeth about equal ; the hmd-feet dentelated at 

 their external edge, and webbed to the ends of the toes ; two great perforations in the bones of the 

 skull behind the eyes, which may be discerned outside the skin. They have only been observed on 

 the eastern continent. 



That of the Ganges (iac. ^a?i.9e/iVa, Gm.), which attains a large size, is remarkable, not only for the length of 

 its muzzle, but for a large cartilaginous prominence surrounding the nostrils, which throws these backwards, and 

 led jElian to assert that the Gangetic Crocodile had a horn at the tip of its snout. 



The Crocodiles, properly so called, — 

 Have the muzzle oblong and flattened, the teeth unequal, but resemble the Gavials in other respects. 

 Some of this form occur on both continents. 



The Caymans, or Alligators {Alligator, Cuv.) — 

 Have a broad and obtuse muzzle, and uneven teeth, the fourth below entering into cavities of the 

 upper jaw, and not the interstices of the upper teeth, as in the preceding ; their feet are only semi- 

 palmated, and undentelated ; and the species are only known to inhabit America. 



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