200 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



So far as we have been able to learn no one, either before 

 or since, has stated any more definite means of distinguishing 

 these more "richly-colored" snakes from those which have 

 been called Pituophis catenifer. 



The present study is based upon nearly 300 specimens of 

 the western races of Pituophis, all but eight of which repre- 

 sent Pituophis catenifer and its subspecies. This material 

 should be large enough to demonstrate any differences in 

 squamation which exists between the two subspecies. Great 

 individual variation is evident in both, but in only one series 

 of scales is there apparent any geographical variation. Only 

 in the counts of the gastrosteges do we find any scale-charac- 

 ter which is of value in the classification of these snakes. 

 While this, in one sense, is disappointing, we nevertheless, 

 must be glad to have found even one character which will aid 

 in the separation of these snakes, since reliance upon color 

 differences, which are subject to so much individual variation, 

 and are so difficult to estimate, has resulted in most unsatis- 

 factory determinations. 



In the series at hand the differences in the number of gas- 

 trosteges in specimens from the northwestern coast counties 

 of California and in others from Arizona, Nevada and Utah 

 is very easily appreciated. If we had specimens only from 

 these localities they might almost be regarded as distinct 

 species, with only an occasional individual of each overlapping 

 the limit of say 230 gastrosteges. Gopher-snakes, however, 

 occur throughout most of the intervening territory and offer 

 gastrostege counts which completely bridge over this differ- 

 ence. We, therefore, must continue to regard these coast and 

 interior races merely as subspecies. 



The number of gastrosteges increases from a minimum of 

 200 in the coast subspecies to a maximum of 263 in the desert 

 subspecies. W^hile individual variation is great in any one 

 locality, it may be said that, in a general way, the warmer and 

 dryer the climate of a given locality the greater the number 

 of gastrosteges. As one proceeds south and east from the 

 cool coast regions toward the interior desert valleys, the aver- 

 age counts gradually increase. 



