'468 REPORT OF NATIONAL MUSEUM, 1898. 



as the tibia. On each side of the base of the tail is a short depressed 

 spine carved a little upward and forward like a spur: and just behind 

 the anus, but exterior to it, and almost covered by the anal flap, are 

 two quite large ones, frilled with a membranous substance. 



A second series of specimens (Cat. No. 3213), probably the males of the 

 preceding, from Camp Yuma, differs from that just described' in having 

 a series of well-defined preanal pores in the centers of six or seven large 

 circular scales between the centers of insertion of hind legs. The pits 

 behind the anus appear tilled with erectile tissue, probably the penis, 

 as the space behind is much swollen or subglobular, with a median 

 longitndinal depression and a deep constriction behind it, beyond 

 which the tail with the larger scales begins at a distance of about 

 twenty one-hundredths of an inch from the anus. This is very differ- 

 ent from the majority of lizards where the tail comes close up to the 

 anal slit. 



It may be that the specimens with preanal pores (Cat. No. 3213) are 

 really of a different species from the typical ones without them. The 

 central row of tubercles beneath the toes is wider and niore transversely 

 lamellar tlian in the type specimen. 



The head is large and broad; convex above and ovate; the width 

 about two thirds the length. It is contained (from snout to ear) a little 

 more than four times in head and body. The hind legs extended for- 

 ward twice; reach nearly to the eye, and are contained about two and 

 one half times in head and body. The hind foot alone is contained six 

 times in head and body. 



The color in Cat. No. 3217 is a light brownish yellow above, with small 

 rounded reddish-brown blotches irregularly distributed. The edges of 

 the eyelids, the nostrils, the tip of rostral, a spot in front of the orbital 

 region, and ten spots on each side of upper jaw are white; tiie rest of 

 upper labials and tip of rostrum reddish brown, like the dorsal blotches. 

 The under parts are opaque silvery white. 



In another series which appears identical with the preceding, though 

 of smaller size, the ground color is brownish yellow, but the back is 

 crossed by six or seven broad bars of olivaceous brown, about equal to 

 each other and to their interspaces. These are continued on the tail 

 as five or six rings interrupted below, tiie borders considerably darker 

 than the centers. The most anterior bar covers the whole head behind 

 the eye. The anterior portion of the head likewise is quite similar, 

 with a U-shaped light mark above the anterior corner of the eye (the 

 concavity anterior), a square spot in the rostral and one around and 

 behind the nostril. The labials are yellowish, with a dusky spot on 

 the end of the lower jaw and another crossing both jaws at about the 

 fourth and fifth labials. The chin is slightly blotched. 



