+8. CROTALUS 933 



Crotalus helleri Meek, Field Columbian Mus., Zool. Series, Vol. VII, 

 No. 1, igo6, p. 17, pi. II (type locality, San Jose, northern Lower 

 California). 



Crotalus sp., Taylor, Univ. Cal. Publ. Zool., Vol. 7, No. 10, 191 2, p. .355. 



Description. — Moderately large. Head broad, flat- 

 topped, varying in outline according to position of fangs, etc. 

 Rostral much higher than wide, in contact with anterior 

 nasal. Two nasals. Usually two (very rarely one) preocu- 

 lars and four internasals. A large scale just in front of 

 supraocular and occasionally large scales on prefrontal 

 region. Supraocular large but not raised into a horn-like 

 process, separated from its fellow by three to nine irregular 

 rows of scales. Twelve to 17 (usually 14 to 16) superior 

 and 14 to 19 (usually 15 to 17) inferior labials, first pair 

 of latter in contact on median line in front of a single pair 

 of genials. Two to four rows of scales between supralabials 

 and eye. Scales in 23 to 27 rows, usually 25, keeled except 

 in one to three rows of each side. Gastrosteges varying from 

 158 to 189; males having from 161 to 186 (usually 169 to 

 180), females from 158 to 187 (usually 175 to 182). 

 Urosteges 14 to 27, a few sometimes divided, males with 

 from 18 to 27 (usually 21 to 25), females with 14 to 24 

 (usually 16 to 20). 



The ground color is brown, olive, gray, or dull yellow, 

 marked along the back with a series of large dark brown 

 blotches which become cross-bars or incomplete rings poster- 

 iorly. These blotches are often paler centrally than about 

 their edges, and vary greatly in shade, shape, amount of 

 separation, and contrast with the ground color. Their 

 number varies from 27 to 41 on the body, and three to nine 

 on the tail. Smaller alternating blotches are usually present 

 on the sides. Many of the scales between or around the 

 dark dorsal blotches are light — yellow, gray or white. These 

 colors often show between the lateral dark blotches also. 



