242 CLASS REPTILIA. 



Snakes (Anguis, Linnaeus), 



Characterized externally by imbricated scales, which 

 cover them completely. They are formed into four 

 subgenera, the first three of which have under the 

 skin, the bones of the shoulder and pelvis. 



ScHELTOPUsiK (PsEUDOPUS,* Mercm.) 



Have the tympanum visible externally, and on each 

 side of the anus a small prominence, in which there 

 is a little bone analogous to the femur, and apper- 

 taining to a true pelvis, concealed under the skin. 

 As to the anterior extremity, it can hardly be said to 

 be visible, there being only a fold, not easily re- 

 marked, and no interior humerus. One of the lungs 

 is a quarter less than the other. The scales are 

 square, thick, semi-imbricated, and between those 

 of the back and belly, are some smaller ones, which 

 produce a longitudinal furrow on each side 



Pallas has made known a species of the South of 

 Russia, which is also found in Hungary and Dal- 

 matia (P. PaUasii, Nob. Lacerta Apoda. Pall. 

 Nov. Com. Petrop. xix. pi. ix. f. 1.), one or two 

 feet in length. The scales of the back are smooth ; 

 those of the tail are carinated. 



M. Durville has discovered another in the Archi- 



* Pseudopus {false foot). I have not been able to perceive, more 

 than M. Schneider, any division at the extremity of this little vestige of 

 foot. 



