13. PHRYNOSOMA 405 



smaller spines behind insertion of thigh. Two series of 

 periphero-abdominal spines, lower series shorter than upper 

 and former of smaller spines. Scales on chest sometimes 

 faintly keeled j those on abdomen and basal part of lower 

 surface of tail smooth ; those on terminal part of tail keeled. 

 Tympanum not covered with scales. Femoral pores vary- 

 ing from 16 to 22. Males with enlarged postanal plates. 

 Tails of females shorter than distance from axilla to front 

 of thigh, those of males considerably longer than this dis- 

 tance. Young of both sexes with short tails. 



The color above is brownish, yellowish or grayish, 

 darker laterally. There is a large brown patch on each side 

 of the neck and a series of three more or less distinct brown 

 bars on each side of the back. These bars are light bor- 

 dered posteriorly. The tail is transversely banded with 

 brown. The belly often is dotted or blotched with black or 

 brown. All these markings are more distinct in the young. 

 The larger dorsal tubercles are often tipped with orange- 

 lufous, and those on each side of the median line have seal 

 brown or black keels. The occipital spines are ribbed with 

 very dark brown. The temporals are yellow, tinged with 

 rufous. In very young individuals the scales of the vertex 

 are grayish or yellowish white, with a few minute brown or 

 black spots. These spots, which are on the raised portions 

 of the scales, become more numerous as the animals increase 

 in size until the whole crown appears black or dark brown 

 crossed by irregular lines formed by the yellow posterior 

 edges of the scales. 



