13. COLUDRID.^ 



6%; and 35 in one, or 6%, the average is 32.1 rows. The 

 gastrosteges vary in number from 221 to 258, males having 

 from 221 to 237, females from 227 to 258; the average in 

 six males is 227, in nine females, 237. The urosteges vary 

 from 50 to 68, males having from 57 to 68, females from 

 50 to 60; the average in six males is 63.5, in nine females, 

 57. 



The dark blotches between head and anus in 1 6 speci- 

 mens vary from 37 to 55, the average being 46. On the 

 tail they vary from 10 to 14, and average 12.5. 



Distribution. — I have examined specimens of the Arizona 

 Gopher Snake taken at Yuma, Yuma County; the Colorado 

 River above Bill Williams River, Mohave County; Cave 

 Creek, Maricopa County; Fort Lowell and the Santa Cruz 

 River near Tucson, Pima County; and the vicinity of Here- 

 ford and Ramsey, Carr and Miller canyons in the Huachuca 

 Mountains, Cochise County, Arizona. Specimens of Pituo- 

 phis from Arizona have been recorded or collected at Oak 

 Orchard, Camp Grant, Wilton Springs, Tucson, Gila River, 

 White River Canyon, Prescott, Walnut, Fort Whipple, Fort 

 Verde, Grand Canyon, Colorado Chiquito, Canyon Diablo, 

 Camp J. A. Packer, Fort Mohave, and at Las Gijas, Pima 

 County. 



Remarks. — The specimens from Mohave and Yuma 

 counties, and a specimen from Silsbee, Imperial County, 

 California, (referred to P. c. deserticola) show more or less 

 intergradation between the Arizona and the Desert Gopher- 

 Snakes. These specimens have very many gastrosteges, 

 while those from extreme southeastern Arizona have fewer. 

 Indeed, some of the latter have so few as to indicate inter- 

 gradation with the gopher snakes of New Mexico which 

 Ruthven has referred to P. c. sayi but which may possibly 



