4 BULLETIN 61, UNITED STATES NATIONAL MUSEUM. 



for a widely ranging and variable group with all the diversities brought 

 about by environmental and racial influences does not furnish the most 

 favorable material for the application of purel}" anah'tical methods. 



An examination of the most comprehensive work that has been 

 done on the garter-snakes will show this. In his "Crocodilians, 

 Lizards, and Snakes of North America" (1900), Cope has described 

 the diversities in an exhaustive way, recognizing in all forty-six 

 forms. Diversity is all that this work reveals, however, and a more 

 minute splitting of the forms would only increase the complexity. 

 Here one is shown the actual living varieties as they exist in North 

 America to-day; the present conditions with all of their anomalies 

 and apparent contradictions, with no key to possible relationships.'^ 

 What is needed, it seems to me, is not more analysis but a greater 

 knowledge of the affinities of the forms, so that the continuity of 

 genetic relationships underlying the present diversities can be grasped. 



METHODS EMPLOYED. 



Three steps are necessary to determine the genetic relationships 

 and simplify Cope's elaborate arrangement of the group: (1) The 

 value of the characters must be determined ; (2) the geographic prob- 

 abilities must be utilized ; (3) similarities and intergradations must 

 be sought. 



It may seem superfluous to insist upon the determination of the 

 value of the characters used in systematic work on this group, for 

 "good" characters, i. e., those which are constant within particular 

 groups, are sought after by most systematists in forming their taxo- 

 nomic groups, but in the sense in which it is here used this rule 

 means more than this, in that it also requires the discovery of the 

 significance of the variations. 



In the work that has been done, as has been said previously, when- 

 ever a more or less stable combination of traits has been observed it 

 has been described as a distinct form, and this with utter disregard 

 as to how the distinctive characters may have been derived. For 

 instance, elegans is separated from radix by the position of the lateral 

 stripe, from parietalis by the smaller number of dorsal scale rows; 

 sirtalis is separated from radix by the position of the lateral stripe and 

 by a difl'erence of two row^s of dorsal scales, from hutleri apparently 

 only by the width of the lateral stripe. In these cases it has been 

 sufficient to ascertain that these characters are little variable within 

 the form, but what relations can be worked out from such facts until 



a It is true that twenty-seven of the described forms are considered subspecies, and 

 a diagram of affinities has been worked out, but the latter is mostly hypothetical, 

 while most of the subspecies are either based merely upon individual variation or 

 are erroneously arranged. 



