6 INTEODUCTOEY. 



III. Theriomorpha. 

 Aglossa . . . Pipa or Surinam Toads. 

 Ranidce . . . Frogs. 

 Hylidce . . . Tree Frogs. 

 Bufonidce . . Toads. 



Chelonia, or Turtles. 



Distinguislied by tlie double sliield in wbicb tbeir bodies are 



enclosed, whether they are terrestrial, fresh- water, or marine. 



The Turtles, Chelonia, have the limbs natatory. 

 Mud Turtles, Trionyx, 



-_ ^ , limbs amphibious. 



Terrapens, J^mys, ) 



Tortoises, Testudo, limbs terrestrial, 



Lacertilia. 

 Having a single transverse process on each side, single-headed 

 ribs, two external nostrils, eyes with movable lids ; body covered 

 with horny, sometimes bony, scales. 



Lacerta — the Monitors, Crocodiles, Lizards ; having ambulatory limbs. 

 Anguis — Ophisaurus, Bimanus, Chalcides, Seps; limbs abortive; no sacrum. 



Ophidia. 



Having numerous vertebrse with single-headed hollow ribs, no 



visible limbs, eyelids covered by an immovable transparent lid ; 



body covered by horny scales. It includes : — 



ViperincB — the Vipers and Crotalidee. 

 Coluhrincs — the Colubers, Hydridse, and Boidte. 



Crocodilia. 



Teeth in a single row, implanted in distinct sockets; body de- 

 pressed, elongated, protected on the back by solid shield ; tail 

 longer than the trunk, comjjressed laterally, and furnished with 

 crests above. The several families are : — 



CrocodiUd<« — the Gavials, Mecistops, Crocodiles. 

 Alligatoridcs — Jacares, Alligators, Caiman.* 



* By some naturalists the Amphibia are considered as a distinct class, by other 

 as a sub-class either of Rptilia or of Tisces. Of the reptiles proper (at present 

 existing), the arrangement into the orders Testiidinata (or Tortoises), Sauria (or 

 Lizards), and Ophidia (or Snakes), is the one most generally adopted; but De Blain- 

 ville elevates the Loricata (or Crocodiles) to the rank of an order, and others have 

 adopted a division of corresponding rank, Saicro^jliidia, for the Anguis series above 

 referred to ; but the latter are merelj' limbless Lizards (or with abortive limbs) akin 

 to the Scinques. — Ed. 



