BUTLERS GARTER SNAKE. 295 



wise so as to form a long narrow scale which is in contact with 

 the first temporal. The gastrosteges vary in number in 20 

 specimens from 131-154 with an average of 139; the urosteges 

 in 19 specimens from 50-71 with an average of 60. The col- 

 oration is remarkably constant, the only differences observed 

 being the presence of lighter ground color in the young which 

 causes the lateral spots to stand out more prominently than in 

 the older specimens, where the color varies to a brownish black, 

 which may quite obscure the spots. 



For convenience, the data on the specimens previously de- 

 scribed and on fifteen specimens which I have examined have 

 been tabulated on following pages. It will be seen from this 

 table that there is, as was shown above, some individual variation, 

 yet the distinctive characters are so pronounced and constant, 

 that in the case of none of the thirty specimens examined was I 

 in doubt as to where to place a single individual. 



AFFINITIES OF BUTLERI. 



Professor Cope's statement, that E. butleri " is remarkably dis- 

 tinct from anything which occurs in the United States " is born 

 out by the specimens now at hand. As was mentioned above, 

 the range of variation is never great enough to make the deter- 

 mination of a specimen doubtful. They resemble in this region 

 the E. sirtalis group more closely than any other, and it was for 

 this reason that Mr. Brown considered his specimens aberrant 

 forms of sirtalis sirtalis. The finding of so many specimens, 

 however, makes this view untenable, and the question then arises, 

 whether it is to be considered as a variety of E. sirtalis, or as a 

 distinct species. 



The number of gastrosteges, and superior and inferior labials 

 are normally less than in any E. sirtalis except E. s. Icptocepliala. 

 The gastrosteges in one instance are I 54, a common number in 

 sirtalis sirtalis, and the supralabials are sometimes seven, the 

 normal number for sirtalis sirtalis which also occasionally has 

 nine infralabials, as occurs in two specimens of butleri. It might 

 seem from this, as Mr. Brown has suggested to me, that butleri 

 bears the same relation to E. s. sirtalis as E. s. leptoccpJiala does. 

 He regards E. s. leptocepJiala as a degenerate form of E. s. sirtalis, 



