378 CLASSIFICATION OF REPTILES. 



rate, rounded, but depressed at the base ; no dorsal 

 crests or anal pores. 



T. undulatus Cuv. Erp. Gen. iv. p. 198. 



Callisaurus De Blainv.* General structure of Phry- 

 nosoma, but the body is slender and lengthened, the 

 neck narrowed, and the Hmbs particularly long and 

 slender; tail long and broad^ depressed at the base, 

 rounded and attenuated beyond ; body enlarged on 

 each side by a development of the skin. 



C. dracono'ides Bl. Nov. Ann. Mus. iv. pi. 24. 



Phrynocephalus Kaup. Tail more or less depressed 

 towards the base, and conic or round beyond, gene- 

 rally prehensile ; head nearly circular, and much 

 flattened ; no external opening of the ears ; tongue 

 entire, triangular; body depressed, wide; toes slender, 

 and fringed on the sides ; scales very small : repre- 

 senting the chameleons. 



P. caudivolvulus. Lepech, pi. 22. figs. 2, 3. 



Megahchilus Eichwald. Tail greatly depressed along 

 its whole length ; the margin of the toes -strongly 

 dentated ; sides of the head with a large ear-shaped 

 membrane ; head flat, nearly circular : representing 

 the genus Draco. 



M. auritus. Daud. pi. 45. fig. 2. 



Agama. Tail very long, slender, rounded, rarely de- 

 pressed, covered with imbricate scales ; nape spined, 

 but no crest or spines on the back or tail. 



Agama Daud. Head depressed; tympanum large, 

 open ; neck, and frequently the ears, armed with 

 difierent-sized spines ; tail very long, slender, with- 

 out any crest, generally cylindrical; tongue emar- 

 ginate ; anal, but no femoral pores ; throat with a 

 fold ; the third and fourth hind toes equal, 

 colonorum. Riipp. ii. pi. 4. sinaita. lb. i. pi. 3. 



• This learned anatomist arranges this form near the dragons, and it IS 

 -not at all unlikely that this may be its natural situation. 



