656 13. COLUBRIDAZ 
Surv. W. rooth Meridian, Vol. V, 1875, p. 611; Coues & Yarrow, 
Bull. U. S. Geol. Surv. Terrs., Vol. IV, 1878, p. 270; Yarrow, Bull. 
U. S. Nat. Mus., No. 24, 1883, p. 141; Taytor, Ann. Rep. Nebr. 
State Board Agricult. for 1891, 1892, p. 349; Cracin, Trans. Kansas 
Acad. Sci., Vol. VII, reprint, 1906, p. 115. 
Heterodon simus kennerlyi Cours & Yarrow, Bull. U. S. Geol. Surv. 
Terrs., Vol. IV, 1878, p. 271; YaRRow, Bull. U. S. Nat. Mus., 
No. 24, 1883, p. 141. 
Heterodon nasicus kennerlyi Core, Report U. S. Nat. Mus. for 1898, 
1900, p. 773. 
Heterodon nasicus nasicus Cork, Proc. U. S. Nat. Mus., Vol. XIV, 1892, 
p- 645; Core, Report U. S. Nat. Mus. for 1898, 1900, p. 774, fig. 
168. 
Description——Head short, little distinct from neck, 
rather broad, with elongate, recurved rostral. Eye moder- 
ately small. Tail short. Rostral large, produced forward 
and upward, bounded behind by first labial, anterior nasal, 
and a number of small plates representing the internasals. 
Plates on top of head are from nine to twenty-five small 
scutes representing the internasals and prefrontals, a frontal, 
a pair of supraoculars, and a pair of parietals. Anterior and 
posterior nasals distinct. Usually two or three small loreals. 
Preoculars and postoculars numerous, joined by a series of 
suboculars which separate eye from labials; about 10 or 11 
scales around eye. Temporals small, numerous, about four 
in first row. Supralabials usually eight, very high, sixth and 
seventh largest. Infralabials about 10 or 11, rarely 12, 
third usually largest, first pair meeting on median line. Gen- 
ials in one pair, or posterior very small. Scales on body in 
23 rows, keeled except in outer rows. Anal plate divided. 
Gastrosteges varying in number from 128 to 150. Uroste- 
ges in two series of from 32 to 47. 
The color above is grayish brown, yellowish gray, or 
yellow, dorsally. Along the back is a series of dark 
blotches. These are rather small, often shorter than broad, 
subquadrate or rounded, more or less indistinctly margined 
