1825.J Mr. Gray on the Genera of Reptiles. 213 



Normal Groups. Anncctant Groups, 



Order V. — SaurophidiL 



1. Sincidag. 3. Typhlopsidse. 



2. AnguidaB. 4. Amphisbsenidte. 



5. Chalcidse. 



The last family agrees with some of the Sauri, in having four 

 legs and plates. 



The first of these columns represents the natural groups 

 which have the characters of the order in the most perfect state, 

 and consequently are not directly allied to the other order, 

 except through the medium of the annectant families, which are 

 the first (No. 3) and last (No. 5) of the right hand column which 

 are themselves united together by the central (No. 4) family of 

 each group. 



The two fossil families may be the type of Emydosauri, but 

 the group is so imperfectly known at present, that it is impossi- 

 ble to determine it. 



Class IV. — Amphibia. 



Body with a soft naked skin ; heart with one auricule and one 

 ventricule ; respiring by lungs and gill, and often by lungs only 

 when perfect ; claws none; headarticulation to the vertebra by two 

 condyles. Blood cold ; windpipe membranaceous ; ribs none, or 

 very short and imperfect ; ^gg skin membranaceous. Animal 

 often changes its form and habit during growth ; egg fecundated 

 after they are deposited, hatched in the water where they are 

 laid. They do not only differ from the perfect animal by having 

 gills, but they often change their external and internal conform- 

 ation, and generally gain legs. 



This class contains so few genera that it is scarcely necessary 

 to divide it into orders. I shall, therefore, for the present merely 

 divide it into families, which may be considered as either, 



§ 1. Undergoing transformation; gills deciduous ; eyelids three 

 distinct: spiracute none. Mutabilia, Gray* The larva elon- 

 gated, respiring by deciduous gills. 



Order \. At^oijiiA, Dumerii, SaUentia, Li/?//'. Batrachein, 

 Blainv. 



Fam. I. RanadxE. 



Body short, thick ; feet four, long ; tail none ; drum of the 

 ear apparent ; sternum and clavicles distinct. Larva elongate 

 tailed, apodous'; gills turfted on four cartilaginous support, co- 

 vered by the skin, pierced with one or two lateral spiracules. 

 fSkin ihining. 



^Hylina 

 Hyla, Lauf. Calamita, Schneid. 



Body slender ; skin mostly smooth ; toes all dilated at the end, 

 the fourth one of the hind feet, of a m derate length, ^ - -^*- 



