Occasional Papers of the Miiseiiin of Zoology 31 



PitiiopJiis catcnifer dcserticola Stejneger. 



Eleven specimens secured in ]\Iaggie Basin and the Cortez, 

 Seetoya and River Ranges. 



Our material seems to lend weight to the view that the 

 Great Basin bull-snakes are recognizably different from those 

 of California, but the dift'erences are so slight and variable 

 that their importance cannot be accurately determined until 

 much more work has been done on the geographical variation 

 within the genus. The number of dorsal scale rows varies 

 within narrow limits. It is 27-25-27-29-27-25-23-21, 27-29-27- 

 25-23-21, 29-31-29-27-25-23-21, and 29-31-29-27-25-23-21. The 

 number of rows of smooth scales varies from 4 to 7, average 

 between 5 and 6. The ventrals var\' from 233-242 in eight 

 females, and are 231 and 236 in two males. The subcaudals 

 vary from 34-38 in seven females and are 61. 61 and 62 in 

 three males. The largest specimen observed measured mo 

 mm. ; the proportionate length of the tail is i2.9%-i8.8% in 

 seven females, 14.3% and 14.6% in two males. The color 

 needs no description except that the dorsal blotches vary from 

 33-66 on the body and from 13-18 on the tail. 



The bull snake is one of the wide ranging species. It was 

 found in the Chrysothamnus zone along the streams, in the 

 sagebrush on the hills and flats on the basin floor, and on the 

 slopes and rock slides and in the canyons of all of the moun- 

 tains (except the Pinyon Range) to the summit of the Carlin 

 Peaks. It is apparently common everywhere, and we could 

 not discover any habitat preference. A large female taken 

 on July 30 contains large eggs. The specimens examined had 

 all eaten small mammals, and to judge by the extent to which 

 the alimentary duct was filled with remains the number con- 

 sumed by this species must be enormous. 



