TEIll) LIZAP.DS OF THE GENUS CNEMIDOPHORUS 191 



by the low-lyiii^- shrubs of tliis sciuiaiid habitat, as well as by the 

 numerous rocks and boulders. 



A habitat of finer sand was found as New Mexico was entered from 

 El Paso. In Dona Ana County this sand was light brown in color 

 and mesquite bushes were very connnon and often low and wide 

 spreading. In Luna County the soil was more loamy and the mes- 

 quite had largely disappeared (vicinity of Cambray) , although yucca 

 and burning bush Avere present. Some grass could be found in the 

 interspaces between the shrubs. Only two specimens were secureil 

 in this environment, while several dozen were taken within a few 

 hours in the sandy " mesquite association " in Dona Ana County. 

 In Grant County, 10 miles south of Steins, the mesquite was more 

 abundant but was accompanied b}^ a mixture of desert shrubbery, 

 such as greasewodd, broomwood, and soapweed. The sand was coarse 

 and there were many large rocks. After a careful search only one 

 specimen was taken, but later at another place (12 miles north of 

 Rodeo), where the sand was finer again, reddish, and more abundant, 

 24 examples were collected within an hour. 



In Arizona the situation w^as much the same as in New Mexico. 

 In Pinal County whiptails were secured in large numbers in various 

 sandy areas where mesquite was the dominant vegetation and in 

 smaller numbers where there Avas less sand and more kinds of 

 shrubbery. In Yuma County gradual transition was noted from a 

 '' mesquite association " to one in which bunch grass was the most 

 conspicuous kind of plant. Here, fine sand was the prevailing type 

 of soil and no great difference in the abundance of whiptails in each 

 of the two habitats could be detected b}^ casual observation. Thus, 

 at this point, the character of the soil, rather than the type of plant 

 life, seems to be the important factor in influencing the distribution 

 of the tessellated lizarcL 



Apparently nothing is known about the Mexican or Lower Cali- 

 fornian habitat of tessellatus and only two short notes have been 

 published concerning the environment in which the various island 

 populations are found. 



Many have been seen "about the deserted nesting burrows of sea 

 birds on Natividad Island " (Van Denburgh and Slevin, 1914, p. 

 145) and numerous other individuals were found "in the small 

 brushy canyons and among fallen cacti " on Isla Partida (Van Den- 

 burgh, 1922, p. 535). 



General hehavior. — These lizards are diurnal in their habits and 

 spend the night in an inactive state. During the day, according to 

 Camp (1916, p. 530), tessellatus "slinks about hesitatingly on the 

 sand, dragging its tail and leaving a characteristic track." These 

 tracks may be seen wherever the sand is loose and the lizards are 

 abundant. 



