276 REPORT OF NATIONAL MUSEUM, 1898. 



seen in this direction .ibont 10 miles east of Liebre ranch. In tbo Avasb leading 

 from the ]\Iobave Desert to Tebachapi Valley it was seen np to 1,030 meters (3,400 

 feet) and may rauj^e higher. It is common in the Lower Sonorau zone at the 

 south end of Owens Valley, and ranges np on the warm cost side of the valley as 

 far as Big Pine. It is common throughout Panamint and Death valleys and in the 

 Amargosa Desert. In Nevada it inhabits the deserts of the southern part of the 

 State, from Ash Meadows easterly across Pahrump and Vegas valleys to the Great 

 Bend of the Colorado, where it is very common, and ranges north through the val- 

 leys of the Virgin and Lower Muddy (where it is abundant) to Pahranagat and 

 Meadow Creek valleys. In western Nevada it comes through Graiievine Canyon 

 (from the northwest arm of Death Valley), ranges easterly over Sarcobatus Flat, 

 and ascends the warm south slope of Gold Mountain, with Larrea, to about 1,640 

 meters (5,400 feet). In Utah it is common in the Lower Santa Clara Valley, but 

 does not range up into the sagebrush or Upper Sonoran zone of the ujiper part of 

 the valley. 



In Desert Valley, just east of the Pahroc Mountains, a form of this species was 

 found which seems to be subspecihcally distinct from the ordinary type. It is much 

 shorter and broader, with a shorter tail, and is bluish gray in color. It may be the 

 same as the animal inhabiting the desert at Pyramid Lake, Nevada, which point is 

 about 2- farther north than Desert Valley, though in the same zoological subzone, 

 for the low altitude of a series of narrow and irregular deserts in western Nevada 

 carries this zone much farther north than elsewhere. These specimens suggest the 

 existence of a form peculiar to the upper division (or Graijia belt) of the Lower 

 Sonoran zone, CaUisaitrua reniralis proper being closely restricted to the lower divi- 

 sion (or Larrea belt) of the same zone. 



UMA Baird. 



Uma I'.Aini), I'roc. Acad. Nat. Sci. Phila., 1858, p. 253. — Cope, Proc. Acad. Nat. 

 Sci. Phila., 1866, p. 310.— Boulenger, Cat. Liz. Brit. Mus., II, 1S85, p. 206. 



A gular fold. Femoral pores present, pierced in an undivided scale. 

 Superciliary scale tectiform. Ears exposed. Occipital small. N^ostrils 

 superior, within the canthus rostralis. Upper labials oblique, angular. 

 Tongue scarcely notched at the end; attached almost to the very tip. 

 Cheek teeth tricuspid. Claws long, acute, with an internal excavation 

 which produces a sharp edge, the base inclosed in a sheath of two large 

 scales. A fringe of free scales on each side of some of the digits and 

 on the external side of the sole. 



This interesting genus differs from CalHsaurus in the lateral instead 

 of vertical direction of its claws, and in the presence of fringes on the 

 borders of its digits and soles. The latter character occurs elsewhere 

 in the Gecconian genus Ptenopus (Gray), which inhabits the deserts 

 of South Africa, and in Phrynocephalus, a genus of Agamidjc which 

 inhabits the deserts of Asia. As the genus Uma is also found in deserts 

 it is ])robable that this structure has a direct relation to the mode of 

 life of the animal. It is probably, like its allies, a swift runner, but 

 rapid progress in the sand is very difficult. The long fringes of stiff 

 scales aid the lizard materially in maintaining a foothold by their pene- 

 trating the sand. It is interesting to iiud this structure present in two 

 genera of such widely diverse affinity and habitat. I append a figure 

 of the foot of the Ptoiopiis [jarnilns, taken from a specimen for the 

 opportunity of studying which I am indebted to Dr. Alexander 



