40. THAMNOPHIS 805 



scale-rows are 19 19 17 in one hundred and thirty-four 

 and 19 21 19 17 in one. The gastrosteges vary in 

 number from 156 to 177, males having from 161 to 175, 

 females from 156 to 174; the average in forty-seven males 

 is 168.7, in eighty-one females, 163.7. The urosteges 

 vary from 74 to 97, males having from 82 to 97, females 

 from 74 to 93; the average in thirty-eight males is 89.8, 

 in fifty females, 82.8. 



There is much variation in color. Certain types of 

 coloration seem to be more frequent in certain localities 

 than elsewhere. Thus, the majority of the snakes from the 

 San Joaquin and Sacramento valleys and the Klamath 

 region differ in appearance from those from Santa Clara 

 County and the southern coast. Much larger series might 

 perhaps throw light upon these conditions, which now are 

 obscure. 



Some specimens have bright red heads. Others, per- 

 haps of the same lot, have no red, or heads that are partially 

 red. The red-headed snakes are of both sexes, various 

 ages, and all sorts of localities. 



Distribution. The Pacific Garter-Snake ranges over 

 most of California excepting the desert areas and the north 

 coast of Del Norte, Shasta, Humboldt, Mendocino, Sonoma, 

 Napa and Marin counties. It is abundant in many parts 

 of this range, and has been reported from western Nevada 

 (Nixon, Pyramid Lake), and southern Oregon (Sycan 

 Marsh, Lakeview, Klamath Falls, Fort Klamath). I have 

 examined specimens from Modoc (Alturas, Likely, Goose 

 Lake, Davis Creek, Warner Mountains, Cedarville), Butte 

 (Oroville), Sutter (West Butte), El Dorado (Fyffe, Lake 

 Tahoe), Placer (Lake Tahoe), Mariposa (Dudley, Yosem- 

 ite Valley, Coulterville, Pleasant Valley), Fresno (Fresno), 

 Kern (Isabella, Weldon, Buttonwillow), Merced (Los 



