VARIATIONS OF GARTER-SNAKES. 



160 



have 8 infralabials on one side, and one from Pullman, Washington 

 (Ruthven collection, No. 11), which has 6 supralabials on one side." 



The extent of the variation in the labial formula may be seen in the 

 diagram (figs. 74-75), for the Montana specimens. The conditions 



a It is worth recording here that a female from Pullman, Washington, which the 

 writer kept in captivity, and which had a labial formula 7/10, gave birth to eleven 

 young none of which had more than 9, while three had 8 infralabials on one side, and 

 none had more than 7, and one had 6-7 supralabials. There is, in regard to the labials, 

 more reduced specimens in this brood than in the series from any other locality. 

 The difference is not geographic, as six specimens from Walla Walla have 7/10, with 

 one exception, in which there are 9 infralabials on one side. All that can be said is 

 that the cause that brought about the reduction apparently affected the entire brood. 



