CROTALUS. 193 
Body rather more elongate than in the allied species, the ventrals being 178-185 in 
number. Scales in twenty-one series, those of the back strongly keeled, the three 
outer series smooth. Head triangular, depressed ; upper surface of the snout in 
front of the supraciliaries covered with enlarged scutes, varying in size and number ; 
crown of the head covered with small smooth scales. ‘Two nasal shields, the anterior 
much larger than the posterior and encroaching upon the anterior and upper surface 
of the snout. Rostral shield reverted above. Nine upper labials separated from the 
eye by a single series of scales. 
Dark greyish-black, with a dorsal series of larger, more or less rounded black spots, 
and two or three lateral series of smaller ones; lower parts blackish ; an oblique black 
band from the eye to the lower part of the neck; it is white-edged above and below, 
the lower edge forming a wide band along the upper labial shields. 
Of the two specimens the larger is 21 inches long; it possesses a strongly compressed 
five-jointed rattle, which has a groove along each side. 
5. Crotalus palmeri. 
? Crotalus tigris, Kennicott, in Mex. Bound. Surv., Rept. p. 14, t. 4; Baird, in Pac. R. R. Exped. 
Report, x. t. 35. figg. 1 a-1g (see also Stejneger, N. Amer. Faun. no. 7, p. 214). 
Crotalus tigris, var., or Crotalus palmeri, Garman, Bull. Essex Inst. xix, p. 124 (1888). 
Hab. North America, ?California and Nevada (Death Valley Lxped.), * Deserts of 
Gila and Colorado (Hennicott)—Muxico, Monclova in Coahuila (Garman). 
6. Crotalus pallidus, sp.n. (Tab. LIX. fig. B.) 
Hab. Mexico, City of Mexico (Doorman). 
Scales strongly keeled, in twenty-five series, the two or three outer ones being 
smooth; none of the scales are striated. As to the scutellation of the head, a small 
pair of internasal scutes may be noticed as well as a larger scute occupying the canthus 
rostralis between the internasal and the supraciliary; the space surrounded by these 
scutes, as well as the rest of the head, is covered by small faintly keeled scales. Nasal 
divided, the posterior portion being much smaller than the anterior. Upper labials 
twelve or thirteen, separated from the eye by two series of scales only. Ventrals 149. 
Upper parts pale brownish, with a dorsal series of about thirty-six rounded or sub- 
rhombic small spots, which are but faintly visible; lower parts uniform whitish. 
A single specimen, 153 inches long; it has a strongly compressed five-jointed rattle, 
grooved along the middle of the side. 
7. Crotalus salvini, sp.n. (Tab. LIX. fig. A.) 
Crotalus molossus, Garman, Bull. Essex Inst. xix. p. 123 (nec Baird & Gir.) (1888). 
BIOL. CENTR.-AMER., Rept., October 1895. *OF 
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