54 ALLIGATOR MISSISSIPPIENSIS. 



Description. The head is elongated, sub-oval, rounded in front, truncated 

 behind, with its sides nearly parallel, only approaching each other about the 

 eighth or ninth superior tooth, and finally meet at "the snout, in a parabolic 

 curve," which makes it resemble the head of a pike, (Esox.) The superior 

 surface of the snout is elevated for the nostrils, and the forehead is sub- 

 divided by a short, sharp carina into two lateral halves; this ridge is peculiar 

 to the Alligator. The internal and superior border of the orbit is raised into a 

 sharp, prominent ridge, divided anteriorly in two short branches, one of which 

 follows the original direction, and the other is turned towards the lateral margin 

 of the jaw; between these two branches begins a furrow, more or less deep, 

 which is continued nearly one half the length of the muzzle. The occipital 

 region is broad, smooth, quadrilateral, and slightly pointed at its two posterior 

 angles. 



The opening of the nostrils are superior near the snout, and directed forw'ards 

 and upwards; and from the earliest moment, as was observed by Cuvier, are 

 separated from each other by a bony plate, which happens in no other of the 

 Crocodile family. The eyes are large and prominent, the pupil elliptical, black, 

 and the iris pale lemon colour, reticulated with dark brown. There are three 

 eyelids, of which the superior is covered with two large plates and several 

 smaller ones. 



The external meatus of the ear is placed on the same line with the orbit, 

 directly behind and near it, and is furnished with two movable lips, one above, 

 the other below, by which it can be closed when the animal is under water and 

 opened when he is on land. 



The jaws are slightly curved or festooned at their borders, and armed with 

 forty teeth above and below; of which the fourth inferior pair is largest of all, 

 and received in sockets of the upper jaw when the mouth is closed. 



The neck is contracted and covered above with plates, smooth or tuberculated. 



