12 REPTILES, 



each foot are armed with nails, all more or less united by membranes; a 

 single range of pointed teeth in each jaw; the tongue fleshy, flat, and 

 adhering close to its edges, a circumstance which induced the antients to 

 believe that they had none ; a single male organ, the anal opening longi- 

 tudinal ; the back and tail covered with very stout, large, square scales or 

 plates, relieved by a ridge along their middle; a deeply notched crest on 

 the tail, which is double at its base. The plates on the belly are smooth, 

 thin, and square. Their nostrils, which open on the end of the muzzle 

 by two small crescent-shaped fissures closed by valves, communicate with 

 tiie extremity of the hind part of the mouth, by a narrow canal which 

 traverses the palatine and sphenoidal bones. 



The lower jaw being continued behind the cranium, the upper one ap- 

 pears to be moveable, and has been so described by the antients ; it only 

 moves, however, with the entire head. 



Their external ear is closed by means of two fleshy lips, and there are 

 three lids to their eyes. Under the throat are two small holes, the ori- 

 fices of glands, from which a musk-scented pomatum issues. 



The vertebra? of the neck rest. on each other through the medium of 

 small false ribs, which renders all lateral motion difficult, and does not 

 allow these animals to deviate suddenly from their course; and it is easy 

 to escape them by turning round them. They are the only Saurians that 

 are destitute of clavicles, but their coracoid apophyses are attached to the 

 sternum, as in all the others. In addition to the common and false ribs, 

 there are others which protect the abdomen, without reaching to the spine, 

 and which appear to be produced by the ossification of the tendinous in- 

 sertions of the recti muscles. 



Their lungs do not dip into the abdomen like those of other reptiles; 

 and some muscular fibres, adhering to that part of the peritoneum which 

 covers the liver, give them the appearance of a diaphragm, whioh, in con- 

 junction with the division of their heart into three chambers, where the 

 blood from the lungs does not mingle so perfectly with that from the body 

 as in other reptiles, approximate them somewhat nearer to the hot- 

 blooded quadrupeds. 



The tympanum and pterygoid apophyses are fixed to the cranium as in 

 the Tortoises. Their eggs are as large and hard as those of a Goose; and 

 the Crocodiles are considered, of all animals, those which present the 

 greatest difference in size. The females keep careful watch over their 

 eggs, and when hatched, tenderly protect their young for some months. 

 They inhabit fresh water, are extremely carnivorous, cannot swallow un- 

 der water, but drown their prey, and place it in some submerged crevice 

 of a rock, where they allow it to putrify before they eat it*. 



The species, which are more numerous than they were thought to be 

 previous to my observations, are referable to three distinct subgenera. 



The Gavials, Cuv., 

 Have the muzzle slender and very long; the teeth nearly equal; the 



* Crocodiles differ so much from Lizards, that several authors have recently 

 thought it proper to form them into a separate order. They are the Loricata, 

 Merreni and Fitzinger; the Emydosauria, Blainv. 



