964 16. CROTALIDE 
Amer. Amph. Rept., 1917, p. 110; Woruies, Univ. Ariz. Agric. 
Exper. Station Bull. No. 83, 1917, p- 359. 
Crotalus willardi Vorutes, Univ. Ariz. Agric. Exper. Station Bull., 
No. 83, 1917, p- 361. 
Description——Size small. Head subtriangular, with 
flattened top. Rostral nearly as broad as high, in contact 
with anterior nasal plate. Two nasals. Two preoculars. 
Usually one loreal, sometimes two. Internasals proportion- 
ally rather large. A large scale just in front of supraocular. 
Supraocular large but not raised into a horn-like process, sep- 
arated from its fellow by from one to three scales. Superior 
labials nine to 11, separated from eye by one row of scales. 
Inferior labials nine to 11, first pair in contact on median 
line. Scales in 21 or 23 rows, keeled except in parts of the 
first and second rows. Gastrosteges varying from 151 to 
162. Anal entire. Urosteges 19 to 27, the first and from 
two to nine posterior usually divided. Rattle very slender 
and delicate. 
The general ground color is olive gray so thickly covered 
with minute brown dots as to give a decidedly brownish 
hue. A narrow dark brown band of uniform width runs 
back and down from the eye, just touching the upper angles 
of the eighth and ninth labials without involving them. 
The scales below this band are vinaceous cream. There are 
two small seal brown spots on the occiput. The genials and 
gulars are yellow, tinged with vinaceous laterally. The rest 
of the head is unicolor. Along each side of the back is a 
series of from 54 to 60 small brown blotches. Anteriorly 
these have a tendency to alternate, but posteriorly they unite 
with one another to form cross-bars. There are seven simi- 
lar brown bars on the tail. The dorsal blotches are seal 
brown, palest centrally, and are edged with very pale brown 
or white. They are about one and one-half scales long, and 
from tvvo to three rows of scales wide. They are separated 
