276 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



EUT-^NIA SIRTALIS PARIETALIS. {Say) Cope. 



Parietal Garter Snake. 



Coluber parietaUs, Say, Long's Exp. E. Mts. i, 1823, 186. — Harl. Journ. Phila. Acad. v. 



1827, 349. 

 Eutainia parietalis,^T>. & GiR. Cat. N. A. Eep. 1853, 28. 

 Eutounia airlalis subsp. parietalis, Cope, Check List N. A. Bat. and Eep. 1875, 41. 



Specimens. 



1180. Chief Mountain Lake. August 19, 1874. 

 1193. St. Mary's Eiver. August 28, 1874. 



Description (No. 1180, Chief Mountain Lake).— This is one of the 

 larger species of the genus, frequently attaining a length of three feet, 

 although, at the same time, the average dimension is less than this. It 

 belongs strictly to the sirtalis group, and in fact is not specifically sep- 

 arable from that species. It is a rather slender and elegant snake j 

 and, when found inhabiting the clear cold mountain streams or lakes, 

 one of the most beautifully colored representatives of the genus, the 

 stripes being firm and bold, and the dark body color being relieved 

 with rich red in marked contrast. The coloration as observed in life in 

 the Kocky Mountain specimens in August is as follows : — 



The dorsal band, which is one scale and two half-scales broad, firm and 

 perfectly continuous from head to end of tail, without indentation for* 

 the dark body-color, is pure yellow, fading to pale naples-yellow in alco- 

 hol. The tint is clearer than that of the lateral bands, which are rather 

 of a heavier golden-yellow from some suffusion with the red that beauti- 

 fully mottles the sides. The lateral stripe is as firm and continuous as 

 the dorsal one, and broader, occupying two whole scales (of the second 

 and third rows). The body-color is black, without obvious shade of 

 brown or olivaceous, speckled between the scales with rich vermilion- 

 red, which is very conspicuous on stretching the skin, forming an in- 

 complete zigzag annulation. This red does not reach as high as the 

 dorsal stripe, but extends through the lateral stripe, and occurs on the 

 first dorsal row as a speck on the lower corner of each scale, and on 

 the corresponding angle of the gastrosteges. The color is chiefly on 

 the skin itself between the scales, but also suffuses the edges of many 

 scales themselves. The first dorsal row of scales, which are much wider 

 than the others, are colored like the belly ; this lighter inferior boun- 

 dary of the lateral stripe causes the stripe itself to appear less firm in 

 outline below than above. The belly is not blackish or even slaty, but 

 of a peculiar pale glaucous-greenish, much as in sirtalis; but black ap- 

 pears as a pair of small, round, lateral spots on each scute at its front 

 border. The head is olivaceous-blackish, the rostral, lorals, and labials 

 being like the belly. Length 31 inches; tail about i of the total length — 

 J of the length of body alone. Gastrosteges 157 ; urosteges 64, all 

 bifid. Superior labials seven on both sides; the fifth largest in this and 

 a second specimen examined. In No. 1180, the labials of the left side 



