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THE AMERICAN NATURALIST [Vol. XLII 



tinguish them sharply on this basis." Thus there is "a marked 

 increase in bright colors in the Pacific coast region in Wash- 

 ington, Oregon and British Columbia," and an increase in this 

 same region "in the amount of black pigment at the expense of 

 the paler colors." "A tendency toward a paler ground color 

 and lighter stripes" is noted in western Texas, southern New 

 Mexico, southern Arizona and northern Mexico, and "a tend- 

 ency toward the production of red pigment on the (ireat Plains," 

 and "toward dark colors in the forest region of eastern United 

 States." 



As a result of these detailed studies of variation and their 

 probable causes and significance, the taxonomy of the group here 

 presented is quite different from that of preceding authors. Only 

 19 "forms" are here recognized, in place of the 30 currently 

 admitted by herpetologists. The author says : 



four great groups or lines of descent in the garter-snakes, but I be- 

 lieve the evidence is sufficient to warrant the assertion." 



These four groups are the radix, sauritus, elegans and sirtalis 

 groups. He explains in a footnote (p. 39) : 



" It is best at the outset to ignore all questions of species and sub- 

 species until their status is established, and to speak of these as forms. 

 Forms, therefore, in the sense employed in this paper, are actual 

 combinations of traits, having geographic extent, irrespective of whether 

 they are isolated (species) or intergrade with their neighbors (sub- 

 species). Detailed discussions of questions of nomenclature are also 

 omitted, although the names are in every ease the ones that, in the 

 light of these investigations, we judge to be the right ones, following 

 the International Code of Zoological Nomenclature. The proper name 

 of each form will be found in the footnotes, together with the 



In the "Table to illustrate the combinations of traits into 

 forms, groups and divisions in the garter-snakes" (pp. 40, 41), 

 the "forms" and "groups," and "primary divisions" (the 

 latter simply numbered I and II) are listed, but it would have 

 been a great convenience if he had given somewhere in his 

 monograph a list of the "forms" with their full names as here 

 employed. The form of nomenclature given in footnotes im- 

 plies the provisional recognition of 12 species (binomials) and 

 seven additional subspecies (trinomials), as follows: 



