VARIATIONS OF GARTER-SNAKES. 



in the belief that the apphcation of these methods to the group of 

 garter-snakes woukl lead to such results, and thus greatly simplify 

 our present knowledge, that this work was undertaken. 



MATERIAL EXAMINED. 



The conclusions reached in this paper are based upon a detailed 

 examination of about three thousand specimens gathered from nearly 

 every part of the known range of the genus,'* so that I believe my 

 knowledge of the variations is well founded so far as it goes. It must 

 be acknowledged, however, that much remains to be done, for, owing 

 to the fact that it has been found impossible to obtain extensive series 

 from many localities, that entire forms are at present known from but 

 few specimens, while in the case of some well-known forms specimens 

 are unavailable from critical localities, it is impossible, in some 

 instances, to do more at present than point out the probable relations, 

 leaving them to be substantiated by detailed work when specimens 

 shall be available. 



One objection to the material that has been used is that it has been 

 largely alcoholic, and it must be admitted that, as some of it has been 

 in preservation for fifty years, it has not always been all that could be 

 desired. This has been more of a limitation to the work, however, 

 than a source of error, for the principal characters employed in the 

 systematic work (scutellation, position of stripes, and tail length) can 

 not become greatly modified in this way, and, although the color may 

 become very much faded, the color pattern may in most cases still 

 be made out. 



A far more important objection to the material is that many of the 

 specimens have but general locality labels, and throughout the pres- 

 ent work it has been continually impressed upon the writer that too 

 much attention can not he paid hy collectors to the securing of detailed 

 locality and habitat data. Specimens that are not labeled accurately, 

 at least as to locality, are almost valueless in this work, while if 

 habitat data were only available in each case much light would be 

 thrown upon the explanation of the present distribution. 



ACKNOWLEDGMENTS. 



In the prosecution of the research upon which this paper is based 

 I have become indebted to a number of persons without whose aid 

 little could have been accomplished. 



I wish first of all to acknowledge my indebtedness to Mr. Charles C. 

 Adams, under whose direction the work has been carried on, for his 



«The specimens examined represent every described form, with the exception of 

 the Eutaenia praeocularis Bocourt (Le Natur, 1892, p. 278), from Belize, British 

 Honduras. I am not certain of the identity of this form. 



