1911] Bryant: Horned Lizards of California and Nevada 21 
There are no records of any species of Phrynosoma from the 
islands off the California coast, although some of the other 
lizards, as, for example, Sceloporus and Uta, are abundant there. 
P. cerrocense is found only on Cerros Island off the coast of 
Lower California. 
The appended map (pl. 8) shows clearly the distribution of 
the five species of horned lizards inhabiting California and 
Nevada. In the preparation of the map only reliable records 
were used. In no case were records incorporated where the sub- 
species could not be differentiated. 
As the map shows, each species inhabits a rather well defined 
region and there is little overlapping of areas of distribution. 
Generally speaking, the distribution of these species conforms 
fairly well to the faunal areas proposed by Van Denburgh 
(1897). According to his analysis, the Colorado and Mohave 
deserts comprise the Desert Fauna; the southern end of the 
state, comprising San Diego (ineluding what is now Imperial), 
Orange, Riverside, San Bernardino, and Los Angeles counties, 
constitutes the San Diego region; the western slope of the Sierra 
Nevadas westward to the ocean, the Californian; a strip along 
the coast, north of Monterey, the Pacific; and the mountainous 
region of the Sierra Nevada, the Sierra Nevadan. Thus, P. 
platyrhinos and A. maccalli would belong to the desert fauna, P. 
b. blainvillei to the San Diegan, P. b. frontale to the Californian, 
Pacific, and possibly the Sierra Nevadan, and P. d. douglassi to 
the Pacific and Sierra Nevadan. 
As might be expected, the desert species, Phrynosoma platy- 
rhinos and Anota maccalli show some special modifications 
which may be related to their environment. The most notice- 
able one is the reduction of the enlarged keeled seales of the 
back. Compared with P. b. blainvillei and P. b. frontale, these 
species present a rather smooth skin made up of small scales 
of unequal sizes and irregular distribution with the spiny scales 
reduced in size. In the ear opening we find the most charae- 
teristic modification, a characteristic which Cope (1898) has 
used in dividing the species into the genera Phrynosoma and 
Anota. In A. maccalli we find the ear opening entirely closed 
and in P. platyrhinos it is covered completely or partially by 
