182 REPTILES. 



E. Body depressed^ with small scales. Back rarely crested. Tail 



conical. 



a. Sides rounded. Femoral and preanal 'pores none. Eyebrow 



scales small. 



44. Leiosurus. Tail with granular scales. Scales under the eye 

 all small. 



45. DiPLOL^MUs. Tail with granular scales, with an elongated 

 scale under the eye. 



46. Tropidurus. Tail round, with rings of large scales. Nape 

 lowly crested. Interparietal ? 



47. Uranocentron. Tail depressed, with rings of large scales. 

 Nape not crested. Interparietal small. 



b. Sides rounded. Femoral and preanal pores distinct, near vent. 



48. Phrymaturus. Tail round, with rings of large scales. The 

 Nape not crested. 



c. Sides with a slight fold. Scales uniform. Body roundish. 



49. Callosaurus. Ventral scales smooth. Femoral pores dis- 

 tinct. 



50. Tropidogaster. Ventral scales 3-keeled. Femoral pores 

 none. 



d. Sides serrated. Body very depressed. Femoral pores distinct. 



51. Phrynosoma. Head spinose. Back and tail with scattered 

 tubercular scales. 



I. Body compressed, covered tvith rings of small, squarish, often 



keeled scales. Perchers. 



A. Nostril lateral, below the eye-ridge. Back not crested. Toes 

 slender, simple. Polychrusina. 



a. Throat compressed and toothed in front. Third and fourth toes 

 subequal. Eyes convex, scaly. 



I. POLYCHRUS, CuV. 



Head 4-sided, short, shelving in front, covered with numerous 

 nearly regular many-sided shields. Throat covered with an ob- 

 lique series of square scales, a small dew-lap toothed in front. Pa- 

 late toothed. Nostril lateral, in a shield, rather behind the top of 

 the nose. Femoral pores distinct. Toes slender, third and fourth 

 nearly of the same length, convex, and covered with very short 



