55o 



COLLEGE ZOOLOGY 



Order 4. Squamata. — Chameleons, Lizards, and Snakes. 

 These animals resemble one another rather closely in structure. 

 They are all protected by horny, epidermal scales, and often by 

 dermal plates of bone. The horny layer of the skin is cast off 

 periodically. The anus is a transverse slit and there are two 

 copulatory organs in the male. The legless lizards and snakes 

 have undoubtedly evolved from ancestors with limbs. In all 

 the living Squamata the limbs, when present, are adapted for 

 walking on land. 



Suborder 1. Rhiptoglossi. — Chameleons. — A number of 

 different kinds of Squamata are called Chameleons, but the true 



Chameleons be- 

 long to the single 

 family Cham^ele- 

 ontid^e of the 

 suborder Rhipto- 

 glossi. There are 

 fifty species, all of 

 which live in Africa 

 and Madagascar; 

 two of them also 

 occur in Spain, 

 India, and Ceylon. 

 The three genera 

 are Chamceleon 



(Fig- 452) with 

 species, and Rhatn- 



452 



■ The chameleon, Chamodeon vulgaris. 

 (From Gadow.) 



forty-five species, Brookesia with three 

 pholeon with two species. 



The Chameleons differ from other Squamata both in external 

 features and in internal structure. The body is laterally com- 

 pressed; the tail is prehensile, is not brittle, and cannot be re- 

 generated if lost; the limbs are long and slender, and the digits 

 are grouped so that two are permanently opposed to the other 

 three; the head usually bears a prominent crest; no tympanum 

 and tympanic cavity are present ; the pectoral girdle lacks clavicles 



