Vol. VIII] VAN DENBURGH AND SLEVIN— GARTER-SNAKES 207 



General Discussion 



Before proceeding- to set forth in detail the results of 

 the present investigation, it may be well to state that the views 

 maintained in 1897 have been, in the main, confirmed. The five 

 forms then recognized, are still recognized, with the same 

 limits, except that the forms then called T. clegans and T. ham- 

 viondii are each divided into two, and all of the forms are re- 

 duced to subspecific rank. 



Each of these subspecies occupies its own particular geo- 

 graphic area, where it alone represents the group ; but the area 

 occupied by each meets or overlaps that of one or more of 

 the other members of the group. Thus, T. ordinoidcs vagrans 

 is the only garter-snake of the clegans type throughout a vast 

 area, where it adheres to its particular color characters with 

 remarkable constancy, but in various places in the far west its 

 range meets or overlaps the ranges of other forms and at 

 these points specimens are found in which the instability of 

 these same characters is quite as notable. Such specimens may 

 defy definite subspecific identification. They are to be regarded 

 as showing intergradation between the subspecies. All of the 

 subspecies recognized are linked one to another by such inter- 

 gradation. 



Some conclusions reached from the present study are : — 



1. T. ordinoides ordinoidcs is the most distinct of these sub- 

 species. 



2. The range of T. ordinoides ordinoides is the coast region 

 of British Columbia, Washington and Oregon. In California 

 it is limited to the extreme northwestern corner of the state. 

 We are unable to follow Brown in referring to T. ordinoides 

 ordinoides the snakes of the coastal strip of California ; or Ruth- 

 ven, in extending the range of this form south to Tehachapi 

 and east to the Sierra Nevada. 



3. The garter-snakes of the immediate coast region of Cali- 

 fornia represent a distinct race or subspecies. 



4. This race may be called T. ordinoides atratus. 



5. Intergradation between T. ordinoides ordinoides and T, 

 ordinoides atratus occurs in Del Norte and Humboldt counties, 



6. T. ordinoides atratus is more closely related to T. ordinoi- 

 des elegans than to the other subspecies. 



