Sauropsida -< 



INTRODUCTION. 



Place in the Animal Kingdom. 

 Sub-kingdom.— VERTEBRATA. 



Section (Huxley). Class. Order. 



Ichthyopsida.. I ^12^[.^.^. 



I. — Chelonia, Tortoises. 



II. — Ophidia, Snakes. 



'Reptilia.-^ III. — Lacertilia, Lizards. 



IV. — Ceocodilia, Crocodiles.* 



and five extinct orders. 

 ^Aves. 



Mammalia. ~ Mammalia. 



The division of zoology, which treats of reptiles, is called 



herpetology ; the sub-division devoted to snakes only is 



called ophiology. 



Snakes may be thus defined : — 



Reptiles of very elongate body, -without limbs or with 

 rudimentary hind limbs scarcely visible from witho"ut ; pro- 

 gressing by means of abdominal plates moved by numerous 

 ribs. The jaws, especially the lower, capable of extensive 

 movement and great expansion; both jaws and palate 

 generally bearing teeth. The external ear absent. The 

 eye unprotected by eyelids. The integument scaly, and 

 the epidermis cast at frequent intervals. 



Some kinds of snakes possess perforated or grooved teeth 

 conveying a poisonous salivary secretion into the system of 

 animals bitten by them. 



* Crocodiles dififer from lizards by possessing a steraum or breast 

 bone. 



