CROCODILIAN8, LIZARDS, AND 8NAKES. 



431 



ridges riuliatiiig from near the center of each scale. There are two 

 gronps of spines on eacli side of the neck, the lower larger. The tail 

 is bordered with a single row of lateral spines and bears a group of 

 smaller ones behind the insertion of the thigh. There are two series 

 of periphero-abdominal spines, the lower shorter than the upper and 

 formed of smaller spines. The scales on the chest are sometimes 

 faintly keeled. Those on the abdomen and basal part of the tail are 

 smooth ; on the terminal part of tail, keeled. The tymi)anum is naked. 

 There are from sixteen to twenty-two femoro-preanal pores. The males 

 have enlarged postanal plates. The tails of the females are shorter 

 than the distance from the axilla to the front of the thigh, but those of 

 the male are considerably longer than this distance. The young of 



Fig. 7fi. 



PlIKYNOSOMA CnUoNATUM HlaINVILLK. 

 = 1. 



San Diego, California. 



Cat. No. 145S7, U.S.N. M. 



both sexes have short tails. The color above is brownish, yellowish, 

 or grayish, darker laterally. There is a large brown patch on ea<;h 

 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-bordered posteriorly. 

 The tail is transversely banded with brown. The belly is often dotted 

 or blotched with brown or black. All these markings are more distinct 

 in the young. The larger dorsal tubercles are often tipped with orange- 

 rufous, and those on each side of the median line have seal-brown or 

 black keels. The occipital si>ines are ribbed with very dark brown. 

 The temples 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 l)lack spots. These spots, which are on the raised 

 portions of the scales, become more numerous as the animals increase 



