128 [{Auausrt, 
Genus CNEMIDOPHORUS. 
A. With eight rows of abdominal scales. 
CnEeMIDOPHORUS MARMORATUS, B. and G.—This species is so closely allied to 
Cn. tigris figured in Stansbury’s Report on the great Salt Lake, that, at first 
sight, it is difficult to perceive the differences. ‘These consist in the proportional 
size of the scales, which are smaller on the back and larger on the tail and belly, 
in Cn. marmoratus than in Cr. tigris. The head is broader on the vertex in Cz. 
marmoratus than in Cz. tugris. Differences in the shape of the cephalic plates 
are likewise obvious when the two species are compared. The hind legs are 
more developed in Cz. marmoratus than in Cn. tigris, the scales which cover 
their under surface are larger and extend overa greater area. The ground color 
is yellowish green, marbled with black, except on the head and posterior part of 
the tail. 
Locality.—Between San Antonio (Texas) and E] Paso del Norte. 
Cnemipopuorus Grauamil, B. and G.—-This is a large and beautiful species, 
strongly suggestive of Cx. tigris, from which it differs by a much smaller and 
narrower head, and by some differences in the proportional size of the cephalic 
plates. The scales on the upper region of the body are still more minute than in 
Cn. marmoratus. Those onthe margin of the subgular fold are much larger than 
in either Cn. tigris and Cx. marmoratus. ‘The head is olivaceous; the ground 
color of the body reddish-green, with seven or eight longitudinal series of sub- 
quadrangular black dots, constituting sometimes continuous bands. This species 
is dedicated to the accomplished officer to whom the U.S. and Mexican boundary 
survey was, for a short time, entrusted. His name has long been associated 
with the progress of science in the United States, from the date of the first ex~- 
pedition of Major Long, to the present time, and we take great pleasure in ten- 
dering this especial mark of respect. 
Locality.—F ound with the preceding species. 
CNEMIDOPHORUS GULARIS, B. and G.—Allied to Cn. sexlineatus, of which it 
has the general appearance. The body, however, is shorter, the fore and hind 
legs are more developed, and the scales on the upper region of the body smaller 
than in the latter species. Another very striking difference is to be found on the 
subgular fold, where the marginal scales are considerably larger than in Cz. 
sexlineatus. 
Localities.—From Indianola, (Texas,) and the valley of the Rio San Pedro, a 
tributary of the Rio Grande del Norte. 
CNEMIDOPHORUS PERPLEXUS, B. and G.—This species-has the general appear- 
ance of Cx. Grahamiz, having like the latter a proportionally small and narrow 
head, which distinguishes at once these from both Cz. tigris and Cn. marmoratus. 
From Cn. Grahamiz it differs by the absence of large scales on the margin of the 
subgular fold. The scales on the upper part of the body are nearly the same, 
but those on the belly are larger in Cz. perplezus than in Cx. Grahamit. The 
ground color is yellowish green, with seven yellowish stripes extending from the 
occiput to the origin of the tail. 
Localities.— Valley of the Rio San Pedro of the Rio Grande del Norte. Speci- 
mens were also collected by Gen. Churchill, on the Rio Grande west of San 
Antonio, (Texas,) and by Dr. William Gambel on his last journey to California. 
CNeEMIDOPHORUS GRACILIS, B. and G.—This species comes nearer to Cn. per= 
plexus than to any other of the same genus, but the head is still narrower, the 
body, tail, aud legs slender, and proportionaliy more elongated. The scales on 
the lower surface of the head and throat are much smaller than in Cz. perplexus. 
The color is bluish black above, with four yellowish white narrow stripes extend- 
ing from the occiput to the origin of the tail. 
Locality.—Desert of Colorado; collected by Dr. John L. Le Conte. 
