332 TKIID^. 



Tail not or but feebly compressed ; dorsal scales small, uniform. 



1. Tupinambis, p. 334. 



Tail strongly compressed, with a double longitudinal keel above ; 

 dorsal scales intermixed with large keeled tubercles. 



2. DracsBna, p. 337. 



2. Ventral plates large, forming less than 20 longitudinal 

 series. 



Ventral plates keeled ; femoral pores. 



3. Centropyx, p. 339. 



Ventral plates keeled ; no pores . . 4. Monoplocus, p. 343. 

 Ventral plates smooth 5. Ameiva, p. 343. 



B. Scaly portion of the tongue arrow-headed, bifid and not re- 

 tractile posteriorly. 



1. Tail rounded. 



a. Teeth longitudinally compressed. 



Head-shields large, regular ; ventral shields in less than 20 longi- 

 tudinal rows 6. Cnemidophorus, p. 360. 



Head-shields small, numerous ; ventral shields in more than 20 

 longitudinal rows 7. Callopistes, p. 375. 



h. Teeth transversely compressed. 



Toes five «. Dicrodon, p. 377. 



Toes four 9. Teius, p. 378. 



2. Tail strongly compressed, bicarinate. 



Dorsal scales small, uniform 10. Crocodilurus, p. 380. 



II. Nasal plates widely separated by one or two frontonasals ; 

 fingers and toes five, all clawed. 



A. Proefrontals present. 



1. Tail compressed, with a double denticulated crest. 



Dorsal lepidosis composed of small scales intermixed with large 

 keeled ones 11. Neusticurus, p. 381. 



2. Tail round or cyclo-tetragonal. 



a. Lingual papillae, oblique plicae. 



Dorsal ecalea large, pointed, strongly keeled. 



12. Alopoglossus, p. 383. 



