ECOLOGY OB" ISLE ROYALE. 333 



soni clearing (II, 1), Shore of Siskowit Lake (V, 1), Sumner Lake (III. 

 5), Tamarack Swamp Rock Harbor (V, 5), and Siskowit Bay. The 

 specimens of this snake obtained vary greatly in color. A number, like 

 the few obtained in 1904, would be referred unhesitatingly to variety 

 parietalis, were it not for the fact that there are other specimens in the 

 collection which have a smaller amount of red on the sides, as well as 

 some in which it is entirely wanting. When the series is examined as a 

 whole it is quite evident that the specimens are intermediate between 

 the typical form and variety paiicUiiis, Avhich is not surprising since 

 the island lies in the latitude of the known "intermediate zone" to the 

 southward (see Euthven, 1908, p. 168). 



This, howevei", in no way vitiates the statement made in 1904 that 

 the presence of this snake on the island is an evidence of a western 

 affinity in the fauna ; for the frequent presence of a considerable amount 

 of red pigment on the sides and the tendency toward the fusion of the 

 upper row of spots, indicate that the Isle Royale specimens are more 

 closely related to the western purictaJis than to the garter-snake of 

 eastern Canada and Northern Michigan, which belongs to the typical 

 form, in that it never has the interspaces of the first row of spots en-- 

 tirely suffused with red, nor the upper row of spots usually fused. 



A number of specimens from Kock Harbor, differ so much from 

 the usual color of Isle Royale specimens as to merit special 

 mention. The ground color in these individuals is black or blackish. 

 The stripes are dark greenish, the dorsal being indistinct. The spots 

 of the first row are distinct, the interspaces being of a light bluish color ; 

 the upper row of spots is usually fused except for short bars or spots 

 of bluish. Belly dark blue with a black band on the outer margin of 

 each scute. Supralabials dark blue, bases of the second to the fifth, 

 white. Iris black. These specimens are identical with those from New 

 Hampshire described by Allen (1899, 64) as pallkluhi ; that they are 

 only dark individuals of the form which inhabits the entire island is 

 shown by the numerous "intermediate" specimens in this collection. 



References. 

 Allen, G. M. 



1899. Notes on the Reptiles and Amphibians of Intervale, New Hamp- 

 shire. Proc. Bost. Soc. Nat. Hist., XXIX, 6.3-75. 

 Bollmau, C. H. 



1890. A Report upon the Fishes of Kalamazoo, Calhoun, and Antrim 

 Counties, Michigan. Bull. U. S. Fish Com., 1888, 219-225. 

 Dickerson, Mary E. 



1906. The Frog Book. New York. 

 Jordon, D. S. and Evermann, B. W. 



1898. The Fishes of North and Middle America. Bull., 47, U. S. 

 Nat. Mus., Vol. II. 

 Ruthven, A. G. 



1905. The Cold-blooded Vertebrates of the Porcupine Mountains and 

 Isle Royale, Michigan. Ann. Rept. Geol. Surv. Mich., 1905, 

 107-112. 

 1908. Variations and Genetic Relationships of the Garter-snakes. 

 Bull. 61, U. S. Nat. Mus. 

 Yarrow, H. C. 



188-3. Check List of North American Reptilia and Batrachia. Bull. 

 No. 24, U. S. Nat. Mus. 



