48 University of California Publications in Zoology (Vou. 9 
but in the late afternoon it is seen scurrying across the sand 
hunting for its inseet food. 
Specimens of this species show the brightest coloration of 
any of the horned lizards under discussion. Several specimens 
from Nevada have bright red markings. As is the case with 
the other species of the genus, the ground color varies with the 
surroundings. Mt. Stejneger (1893), in his notes on the reptiles 
collected on the Death Valley expedition, says: ‘‘The specimens 
collected by the expedition vary from a very pale, in some nearly 
whitish, drab gray to a vivid brick-red. At Ash Meadows in 
the Amargosa Desert a very white form was found living on 
the white alkali soil.’’ 
DISTRIBUTION 
P. platyrhinos inhabits the Lower Sonoran deserts of the 
Great Basin from California to Utah. The type locality is 
Great Salt Lake, Utah. In the mountains it often ranges a 
short distance into the Upper Sonoran Zone, for it has been 
taken at an altitude of 5700 feet in the Argus, Funeral, and 
Panamint mountains. This is the common horned lizard of 
Nevada and of the Colorado and Mohave deserts of California. 
No record of its occurrence in northern California is known. 
but it doubtless does occur in Lassen and Modoe counties, for 
it is common just across the line in Nevada. In Imperial County, 
California, this species overlaps the territory occupied by Anota 
maccalli, both species having been taken at Mecca. This loeality 
probably marks its southern limit. Specimens of P. platyrhinos 
and P. blainville: frontale have been taken in Walker Pass and 
on the south fork of the Kern River, indicating that an over- 
lapping of distribution areas takes place in this region. 
The type locality (Death Valley, California) of a horned 
lizard described by Cope (1896) under the name Anota calidia- 
rum lies within the territory oceupied by P. platyrhinos. The 
diagnostic characters used by Cope in his description show P. 
calidiarum (Anota calidiarum) to be very closely allied to P. 
platyrhinos. He says: “‘This species is nearest to the A. platy- 
rhina Girard, from which it differs in various respects. The 
general proportions of all the parts and the coloration are about 
