152 3. IGUANID& 



trasted with the blue patches, and often are joined together 

 below. In females the lateral blue patch is absent and the 

 dark blotches are gray. Some males have a reddish or 

 orange suffusion on the back, gular region and axilla. 



Length to anus 80 85 93 96 98 100 



Length of tail 111 119 127 124 134 121 



Snout to back of inter- 

 parietal 14 14 16 17 16 16 



Snout to ear 16 16 17 18 18 17 



Width of head 13 14 14 15 15 15 



Fore limb 46 47 49 52 50 50 



Hind limb 80 80 85 86 84 84 



Base of fifth to end of 



fourth toe 32 33 33 32 32^ 32 



Distribution. This species occurs on Tiburon Island, 

 in the Gulf of California, and on the mainland of Sonora, 

 Mexico, where it has been taken at Tepoca Bay, San Pedro 

 Bay, Guaymas, and probably San Miguel de Horcasitas. 



Remarks. This large species is very closely related to 

 C. v. ventralis. The average number of its femoral pores 

 is a little greater. It may be easily distinguished by the 

 obsolete, poorly defined, lateroventral black blotches of the 

 males, and the fact that these blotches frequently are united 

 ventrally. In all the other species these blotches are well 

 defined, intense black in sharp contrast. 



26. Callisaurus ventralis ventralis (Hallowell) 



DESERT GRIDIRON-TAILED LIZARD 



Plate 12. 



Homalosaurus ventralis HALLOWELL, Proc. Acad. Nat. Sci. Phila., Vol. 

 VI, 1852, p. 179 (type locality, New Mexico); HALLOWELL, Sit- 

 greaves' Exped. Zufii and Colorado Rivers, 1853, p. 117, pi. 6; 

 HEERMANN, Rep. Pac. R. R. Surv., Vol. X, 1859, p. 24. 



