NINTH ANNUAL REPORT. 199 
time its striking blue-gray color has attracted considerable in- 
terest. The snake presents the appearance of being coated with 
pumice dust. 
CROMAEUS*BUEVIS: See NOV. 
GRAY RATTLESNAKE. 
Locality—This specimen was captured twenty miles inland 
from Managua, Nicaragua, in avery dry, sandy district. 
Relationship.—The species is most nearly related to Crotalus 
duUrissus (terrificus ) of Mexico, Central and South America, from 
which it differs in the following characters: 
The much smoother character of the scales of the head; 
The less tubercular striation of the scales of the dorsal 
region ; 
3. The entirely different ground color, and almost total absence 
of color pattern; 
4. Its small size at maturity. The specimen described is adult, 
yet it measures but a trifle over two feet in length, while C. duris- 
sus attains a length of six feet. 
Scalation.—On the upper surface of the snout are three pairs of 
plates, the central pair much the larger, and extending to about 
one-third the length of the supraoculars. There are three rows 
of flat scales between the central portion of the supraoculars. 
The central portion of the top of the head is covered with small, 
almost smooth scales. The scales of the temporal region are 
strongly keeled, although the carinae are not so sharply raised as 
with C. durissus. There are thirteen superior labials. Four rows 
of scales separate the eye from the labial plates. 
The dorsal scales are in twenty-seven rows. All but the first 
and second rows are strongly carinated, those of the median 
region possessing tubercular carinae, though this character 1s 
considerably less pronounced than with the related species. A 
count of the abdominal plates and urosteges shows 167 of the 
former and 23 of the latter. The anal is entire. 
Coloration—The color is uniform pale, bluish-gray above, 
matching the tint of pumice-stone. There is practically no color 
pattern. Immediately after the epidermis has been shed, a chain 
of very obscure rhombs, of a slightly darker tint than the body 
color, may be discerned if the skin is distended. There are no 
traces of head-markings. The upper surface of the tail is of the 
same general color as the body. The abdomen and first row of 
scales are pinkish-white, which tint is deeper on the outer edges 
of the gastrosteges. 
