478 CLASS REPTILIA. 



All the under part of the cranium is flat, and formed by 

 a single sphenoid. There are but two tympanic bones, two 

 petrous portions, and two occipitals, and the fenestra ovalis 

 is entirely pierced in the petrosum. 



The nostrils, without any osseous envelope, externally or 

 underneath, penetrate into the mouth under the lower lip. 



The under jaw has its dentary edge furnished with teeth. 

 Its coronoid apophysis strongly marked, gives attachment to 

 a crotaphite muscle, which passes over the pterygoidean bone, 

 and produces the swelled appearance of the head. 



Between the head and pelvis are thirty vertebra, and 

 twenty-five from the pelvis to the end of the tail. All, ex- 

 cept the very last, are well ossified, and articulated as in the 

 first by concave faces filled with cartilage. 



On each side, from the second vertebra, are seven rudi- 

 ments of ribs, very small, and the head of which is not 

 divided. 



Except the neck of the omoplate, all the rest of the 

 shoulder is cartilaginous. The pericardium is enveloped by a 

 cartilage, which might almost pass for the remains of a sternum. 



The pelvis is still less ossified than the shoulder, and the 

 bones of the feet which are very small and slender, have 

 cartilaginous extremities. 



We shall conclude this account of the reptiles with a few 

 brief remarks, on the generic peculiaries of the Siren. 



This animal, of which the species lacertina attains the 

 length of more than three feet, is of the number of those 

 beings, which seem peculiarly formed to set classification at 

 defiance, and which are distinguished in the Animal King^^ 

 dom, for the anomalies of their organization. It inhabits the 

 marshes of Carolina, and especially those devoted to the cul- 

 ture of rice, where it lives on earth-worms, insects, young 

 mollusca, &c., at least according to the report of professor 

 .Barton, who denies it the faculty of devouring serpents. It 



