Vol. VIII] 



VAN DENBURGH AND SLEVIN— GARTER-SNAKES 



203 



The following localities are represented each by one speci- 

 men. The material being so limited we are unable to state 

 definitely to which subspecies of sirtalis these specimens should 

 be referred. 



1. Willow Lake, Tehama Co., California. 



2. Susanville, Lassen Co., Cal. 



3. Fallen Leaf Lake, El Dorado Co., Cal. 



4. Silver River, Harney Co.. Oregon. 



5. Vicinity Nixon, Washoe Co., Nevada. 



Remarks. — This subspecies differs from both T. s. parietalis 

 and T. s. concinniis in having a greater number of gastrosteges 

 and urosteges. This is clearly shown in the following table of 

 average counts : 



Gastrosteges ^ 5 



parietalis 165.4 16L1 



concinnus 164.3 156.4 



infernalis 168.7 163.7 



Urosteges 



parietalis 85.2 76. 



concinnus 84.2 76.8 



infernalis 89.8 82.8 



It probably will prove to be impossible to draw any very 

 definite limits to the areas occupied by this form and by T. s. 

 concinnus. This must be so, for one gradually changes into the 

 other. The area of intergradation is a broad one, individual 

 variation is great, and opinions may easily differ as to geo- 

 graphical limits. Our own views are expressed in the lists of 

 localities given under each subspecies. These indicate that to 



