1922| Schmidt, Amphibians and Reptiles of Lower California 037 



Santa Catalina Island is a juvenile one, the smallest in the series, but 

 apparently indistinguishable from the mainland specimens. 



Dipso-saurus dorsalis dorsalis (Baird and Girard) 

 Crotaphytus dorsalis Baird and Girard, 1S52«, p. 126. 

 Dipso-saurus dorsalis Stejneger and Barbour, 1917, p. 44. 



Range. — Colorado and Mohave Deserts, east to the Colorado River, northern 

 Lower California. 



Lower Californian Records. — San Felipe, Meek, 1905, p. 4; San Xavier, Van 

 Denbnrgh and Slevin, 1921o, p. 56. 



Specimens in the Biological Survey collection from northern Lower 

 California come from Volcano Lake (U. S. N. M. No. 37631), and San 

 Felipe Bay (37632). I have also referred Meek's specimen from San 

 Felipe to the typical subspecies. The area of intergradation between 

 the two forms remains to be determined. 



Crotaphytus collaris baileyi Stejneger 

 Crotajihytiis baileyi Stejneger, 1890, p. 103, PI. xn, fig. 1. 

 Crotaphytus collaris baileyi Stejneger and Barbour, 1917, p. 45. 



Range. — Northern Mexico, Arizona, the Great Basin; east in southern New 

 Mexico to southwestern Texas; west to eastern California and Lower California. 



Lower Californian Records. — San Felipe, San Salado, Meek, 1905, p. 8; 

 (observed at Canon Esperanza and Trinidad by Heller) ; Cerro de las Palmas, Moc- 

 quard, 1899, p. 303. 



Specimens in the Biological Survey collection come from Volcano 

 Lake (U. S. N. M. No. 37625) and San Pablo (37626). The juvenile 

 specimen from San Pablo, in the same general area as the type locality of 

 Crotaphytus fasciatus Mocquard (1899, p. 303, PI. xm, fig. 1), is of 

 especial interest for comparison with this form. Mocquard's specimen 

 measured 113 mm. in length, of which the body occupied 40 mm. They 

 are consequently of approximately the same age. The coloration of the 

 back, black with six transverse white lines, is almost exactly the same, 

 Mocquard's specimen having an additional white line. This coloration 

 corresponds with that described by Cope (1900, p. 249) as the juvenile 

 coloration of C. collaris. Unfortunately I have no juvenile collaris of 

 comparable age at hand, but I am convinced that fasciatus is merely a 

 juvenile color phase. The characters other than coloration employed by 

 Mocquard to distinguish C. fasciatus are either juvenile or inconstant. 



