560 REPORT OF NATIONAL MUSEUM, 1898. 



I. Anterior nasal plates not separated by the frouto-nasal ; limbs well developed; 



A. Scaly portion of the tongue not much widened, and not or but feebly eniar- 

 giuatc posteriorly, frequently retractile into a basal 

 sheath. 



1, Ventral plates small, forming more than 20 longitudinal series. 



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



Tupinamhis Daudin. 

 Tail strongly comjjressed, with a double longitudinal keel above; dor- 

 sal scales intermixed with large keeled tubercles. 



iJracana Daudin. 



2. Ventral plates large, forming less than 20 longitudinal series. 



Ventral plates keeled ; femoral pores Centropyx Spix. 



Ventral plates keeled ; no pores Monoplocits Giinther. 



Ventral plates smooth ; no femoral pores Tejaporus Cope. 



Ventral plates smooth ; pores Jyneiva Cu vier. 



AA. Scaly portion of the tongue arrowheaded, bifid, and not retractile posteriorly. 



1. Tail rounded. 



a. Teeth longitudinally compressed. 



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

 tudinal rows Cnemidophorits Wagler. 



Like Cnemidophorus, but frontoparietal plates fused together. 



Veriicaria Cope. 

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



longitudinal rows Callojnstes Graveuhovtit. 



aa. Teeth transversely compressed. 



Toes five Dicrodon Dum^ril and Bibron. 



Toes four . Teiiis Merrem. 



2. Tail strongly compressed, bicarinate. Dorsal scales small, uniform. 



Crocodihii'us Spix. 



II. Nasal plates widely separated by one or two frontonasals; hngers and toes five, 



all clawed. 

 A. Pnefrontals present. 



1. Tail compressed, with a double denticulated crest. 



Dorsal lepidosis composed of small scales intermixed with large keeled 

 ones Neustivurus Dumeril and Bibrou. 



2. Tail round or cyclo-tetragonal. 



a. Lingual papilla;, oblique plicte. 



Dorsal scales large, pointed, strongly keeled; ventrals imbricate; 



collar obscure A loponlosmin Boulenger. 



Ventrals truncate; collar well defined; dorsals in transverse rows. 



Ptyclioglossus Boulenger. 

 aa. Lingual papillte normal, scale-like. 

 a Dorsal scales irregular and of diHercnt sizes. 



Posterior head scales small : gular scales irregular, no collar nor 



femoral pores Echinosuura Boulenger. 



a Dorsal scales strongly keeled. 



* Dorsal scales arranged in regular transverse and oblique 

 series. 

 t Claws well developed, curved. 



Ventrals like the dorsals, keeled Leposoma Spix. 



Ventrals quadrate, smooth; no collar ..LoxophoUs Cope. 

 Ventrals quadrate, smooth ; a collar. 



Pantodactylus Dumeril and Bibron. 

 t t Claws small, straight, conic. 



Ventrals like dorsals, keeled; no collar; femoral pores 

 present Miouyx Cope. 



