1904.1 



NATURAL SCIENCES OF PHILADELPHIA. 



471 



is of interest here to note that certain garter snakes from Indiana, 

 about the eastern limit of E. radix, called by Cope E. butleri, show irreg- 

 ularities in the position of the lateral stripe perhaps indicating transi- 

 tion. E. radix is a connecting link on the one hand with E. proxima 

 of the Mississippi valley, which in the east has given off E. saurita 

 and E. sackeni, and on the other, in the southwest with E. 7negalops 

 and doubtles other Mexican forms. 



If this hypothetical family-tree of Eutasnia is correct, an interesting 

 lesson in lines of dispersal of Austroriparian genera may be gained 

 from their diagrammatic representation : 



E. s. leptocephala 

 E. s. pickeringi 



E. e. elegans 



E. e. vagrans 



E. hammondr 

 E. eques/ 



E. marciana 



E. megalops 



E. s. parietalis 



E. radix 



E. s. ordinatus 

 -E. s. sirtalis 



E. proxima 



E. saurita 



E. sackeni 



Of the remaining so-called Natricinae, all of which are small and 

 more or less degenerate representatives of Tropidonotus and EutoBnia 

 or of the stock from which they came, the most widely spread genera, 

 Storeria, Haldea and Virginia are chiefly Atlantic, Seminatrix is 

 wholly Ocmulgian, Tropidoonium, of limited range and probably of 

 relatively late origin, belongs to the Mississippi valley, and the very 

 few specimens of Amphiardis known are from Dallas, Texas, on the 

 western borderland of the Austroriparian. 



Among other widely ranging genera, Zamenis is an ancient form 

 whose present distribution includes also the Palsearctic and Oriental 

 regions. The earliest Nearctic style seems likely to be represented by 

 Z. flageUum flagellum, which belongs to the Ocmulgian centre. The 

 young of this species show narrow cross-bands, and occasionally much 

 wider ones, as well as a tendency to form narrow stripes on the centres 

 of some of the lateral scale rows, all of these being present as diagnostic 

 characters in various combination in adults of most other American 

 species. The inequality of color between the anterior and posterior 

 portions of the body, characteristic of all, is most pronounced in 

 Z. f. flagellum. 



