244 REPORT OF NATIONAL MUSEUM, 1898. 



than elsewhere, each scale conspicuously keeled. The other scales 

 above about equal, slightly reticulated and diamond-shaped, each one 

 with a slight keel. Scales on the belly similar, but larger; those on the 

 sides smaller than either. Scales on the tail keeled, on the belly 

 smooth. Tail compressed; about twice as long as the body. Auditory 

 aperture vertically elongated, with the anterior edge dentated. Infra- 

 orbital chin composed chiefly of one single horizontal plate. Femoral 

 pores distinct in the adult male. 



Head very short, not one- fifth the length from snont to anus. Hind 

 foot not quite two-fifths this length. Tail twice as long. It is readily 

 fractured, differing in this respect from the species of Grotaphytus, where 

 it is" quite tough. 



General color in alcohol brownish yellow, the sides and legs marked 

 with lines of brownish red, which anastomose to a greater or less extent 

 and inclose rounded or polygonal yellowish blotches, which are less 

 distinct on the back; the under part generally yellowish; the tail with 

 an alternation of nearly equal yellowish and brownish rings interrupted 

 below. 



In young specimens there are two blackish spots above each shoulder. 

 The side of the head is barred vertically with bluish, the chin and 

 throat faintly blotched with the same. The orbits are dusky, with a 

 yellow bar at each end of the eye. 



This species ranges from Cape St. Lucas along the gulf coast of 

 Lower California to the Colorado and Mohave deserts. To the east it 

 extends at least as far as the Colorado River, but how far beyond is 

 not known. Its northern range is indicated below. 



In regard to the habits of Dipsosaiirus dorsalis, Dr. Merriam remarks^ 

 as follows : 



This remarkable lizard is more strictly limited to the torrid Lower Sonorau Zone 

 thau any other species, not excepting the gridiron-tail {CalUsaiu-iis ventralis). It 

 ranges across the Lower Sonoran deserts of the Great liasin from the Mohave Desert 

 and Death Valley to the Great Bend of the Colorado River, and thence northerly in 

 eastern Nevada through the lower part of the valleys of the Virgin and Muddy, 

 always keeping within the Larrea belt. In western Nevada it reaches its northern 

 limit in the Amargosa Desert, and was not found in Oasis Valley or Indian Spring 

 Valley. In the northwest arm of Death Valley it does not range northward beyond 

 Grapevine Canyon, and in Owens Valley was not found much north of the lake. It 

 is a strict vegetarian, feeding on buds and flowers, which it devours in large quan- 

 tities. No insects were found in any of the stomachs examined; some contained 

 beautiful bouquets of the yellow blossoms of Acacia, the orange ^ralvastrum, the 

 rich i^urple Dalea, and the mesquite {Prosoim juUjlora) ; others contained leaves only. 



1 North American Fauna, No. 7, 1893, p. 164. 



