574 VIPERID&. 
Crotalus horridus, part., Gray, Cat. p. 20 (1849). 
—— molossus, Baird & Gir, Cat. N, Am. Rept. p . 10 (1858), and 
Rep. U.S. Mex. Bound. ats ii, Rept. pl. ii. (1859) ; Garm. Bull. 
Essex Instit., xix. 1888, . 128; Cope, Proc. US. Nat. Mus. xiv. 
1892, p. 688 ; Stejneger, Rep. U.S. Nat. Mus. F. 18983, p. 424 Pre 
—-— ornatus, Hallow. Proc. Ac. Philad. 1854, p. 192, and Rep. U.S, 
Surv. R. R. x.y Parke’s Rep. p. 28, pl. ii. (1859). 
durissus (non L.), Cope, Proc, Ac. Philad, 1859, p. 337 ; Garm. 
N. Am. Rept. p. 111 (1888) ; Cope, Proc, U.S. at. Mus. xiv. 
1892, p. 688. 
Cundisia basilisea, Cope, Proc. Ac, Philad. 1864, p, 166, and 1866, 
308. 
aE quel Cope, Proc. Ac. Philad. 1866, p. 308. 
molossus, ope, Le. 
Crotalus rhombifer (non Latr.), Duges, Naturaleza, iv. 1877, p. 22. 
basiliseus, Cope, Proe. mer, Philos, Soc. xxii. 1885, p. 180; 
Duges, Naturaleza, (2) i. 1888, p. 183; Cope, Proc. U.S. Nat. 
Mus, xiv. 1892, p. 688, 
—— terrificus, Cope, Proc. U.S. Nat. Mus. xiv, 1892, p. 688. 
horridus, var. unicolor, v, Lidth de Jeude, Notes Leyd, Mus. 
ix, 1887, p. 133. 
Snout very short, with obtuse canthus. Rostral as deep as 
broad or a little deeper than broad, in contact with the anterior 
nasal; upper surface of snout covered by a pair of internasals and 
a pair of prefrontals, rarely with one or two small shields between 
them ; scales between the supraoculars often more or less enlarged 
or shield-like, in two to five longitudinal series ; three or four series 
of scales between the eye and the upper labials; latter, 12 to 17. 
Scales in 23 to 31 rows, dorsals very strongly keeled. Ventrals 
160-199; anal entire; subcaudals 18-30. Brown above, with a 
series of ‘darker, light-edged rhombs, often lighter in the centre, in 
contact with one another or narrowly separated, or with decussating 
yellow lines; occiput and neck with or without two more or less 
distinct dark parallel stripes ; a dark streak from the eye to the 
angle of the mouth, and often another from the loreal pit to below 
the eye or beyond; the markings sometimes indistinct ; yellowish 
white beneath, uniform or spotted with brown ; tail usually brown 
or blackish, 
Total length 1320 millim. ; tail 130. 
Arizona, New Mexico, and Texas to Southern Brazil and 
Northern Argentina, 
A. Stripes on the neck absent or ill-defined. 
a-b. Her. (Sc. 27,27; Presidio, W. Mexico. a A. Forrer pay 
v. ie 191; ©. 24, F. D. Go 
30). Eaq. [P.]. 
e, d. g (Se. 27,23; V. City of Mexico. Mr. Doorman [C.}. 
’ 178, 170; O. 24, 26). 
e. ig . (Se. 20; V. Mezquital del Oro, Zaca- Dr. A. C. Buller [C,}, 
2; a) 27). tecas. 
I- ih ir oo 25; V.170; 8. Mexico, F. D. Godman, Esq, 
©, 24) & hgr. (Se. 25, (P.}. 
+i v1 178, 174; 0. 
18, 18). 
