98 



CALIFORNIA ACADEMY OF SCIENCES. 



CalUsaurus dracontoides. 



1880, Lockington, Am. Nat., p. 295. 



(?1889, Cope, Proc. U. S. Nat. Mus., p. 147.) 



1890, Townsend, Proc. U. S. Nat. Mus., p. 144. 

 CalUsaurus ventralis. 



(1893, Stejneger, N. A. Pauna, No. 7, p. 171.) 



This more northern species is quite distinct from C. 

 draconoides of the "Cape Region," and may be readily- 

 distinguished from it by the following characters: 



C ventralis. 

 Large. 



Snout short and rounded. 

 Supralabials profniuent and very 



convex in lateral outline. 

 Males with two large oblique black 



blotches on each side. 



C. draconoides. 



Small. 



Snout longer and less rounded. 



Supralabials much less prominent and 

 convex. 



Males with two smaller almost verti- 

 cal black blotches, followed by a 

 small black sjjot. 



No intergradation of the two forms has yet been shown, 

 but two young females from San Ignacio, and one from 

 Santa Margarita Island, are more nearly like C. dracon- 

 oides than are any of the other specimens of C . ventralis., 

 suggesting, but not showing, an instability of character 

 farther to the south. 



The following measurements of C. ventralis are given 

 for comparison with those of C . draconoides : 



Sex 



Snout to vent 



Tail 



Head to ear 



Width of head 



Head to posterior edge of interparietal 



Hind limb 



Fore limb 



Base of fifth to end of fourth toe 



i, 



i, 



5 



<? 



? 



86 



88 



81 



82 



72 



117 



— 



— 



107 



102 



16 



16 



15 



16 



15 



14 



13 



13 



14 



13 



15 



15 



14 



14 



13 



79 



— 



75 



76 



70 



49 



46 



40 



45 



42 



35 



— 



32 



33 



31 



9 

 74 

 98 

 14 

 13 

 13 

 65 

 41 

 30 



This species has been recorded from San Luis Gon- 

 zales Bay, and Angel de la Guardia Island. It is com- 



