LACERTIANS. 255 



TVopidosaurus, Lacerta, Ophiops, Calosaurus, Eremias, Scapteira, 

 Acanthodactylus and Psammodroma. 



In the genus Crocodilurus, the intermaxillary bone supports eleven 

 small, conical, simple teeth ; behind which there are, on each side, 

 from fifteen to seventeen maxillary teeth ; these are of larger size, 

 compressed, the first four or five pointed and slightly recurved ; the 

 rest straight and with the summit tricuspid, at least in young indivi- 

 duals : these hinder teeth have the form of rounded tubercles in old 

 specimens. The teeth of the lower jaw resemble those above : there 

 are about twenty-two on each side. 



The intermaxillary teeth of the bicarinated Lizard {Thorictes 

 Dracaena, d. & b.) are nine in number, conical, slightly compressed 

 from before backwards : there are about ten superior maxillary teeth 

 and twelve inferior maxillaries on each side : the first four or five in 

 both jaws are conical, but with obtuse summits, the posterior ones 

 present the form of very large tubercles, (PI. QQ, fig. 5).(1) 



The intermaxillary teeth of Neusticurus are twelve in number, 

 of a simple conical form : there are twenty-two maxillary teeth on 

 each side, compressed, all obtusely tricuspid. The lower jaw supports 

 thirty-five teeth on each side : the first five or six being conical, and 

 all the others flattened laterally, and divided into three obtuse 

 cusps. 



In the Aporomera, the intermaxillary teeth are small pointed 

 cones slightly recurved : the maxillary teeth and the corresponding 

 teeth of the lower jaw are long, strong, separated, pointed, arched 



(1) " II est tres-prubable qu'a une epoque moins avancee de leur vie les Thorictes, de merae 

 que les Sauvegardes, chez lesquelles I'age rend les dents maxillaires posterieures tubercu- 

 leuses, ont ces memes dents, plus ou moins comprimees et divisees a leur sommet, soit en deux 

 soit en trois points mousses, (p. 52, torn, v., Dum. and Bib. Erpetology). That the same 

 tooth should change a bicuspid or tricuspid for an obtuse crown through the attrition to which 

 they are subject during life, and thus exhibit a tubercular character in age might be conjectured 

 with great probability of a mammiferous animal, as, indeed, such a circumstance not unfre- 

 quently occurs in that class, in which the teeth are replaced in vertical succession but once, 

 and the second series are long retained : but that such change of form and function should 

 take place in the same tooth seems incompatible with the physiological laws of dental decadence 

 and reproduction in the cold-blooded animals. No doubt the young Draccence have their teeth 

 fitted for insect food ; but these are probably shed, and the molar type gained by a succession 

 of new teeth. 



