20 CALIFORNIA ACADEMY OF SCIENCES. 



The following species and subspecies have been found 

 in Nevada: 



Gopherus agassizii, Heloderma suspectum, 



Dipsosaiirns dorsalis, Ciiemidophorus tigris, 



Callisaiirus ventralis, Cbaiina bottfB, 

 Holbrookia oiaculata approximaus, Lampropeltis boylii, 



Crotaphytns baileyi, Salvadora grahainue, 



Crotaphytiis wislizeuii, Bascanion flagellum fveuatum, 



Saiiromahis ater, Bascauiou taaniatiim, 



Uta stansburiana, Pituophis catenifer deserticola, 



Uta graciosa, Thamuoijhis parietalis, 



Scelopoms graciosus, Tbamuopbis vagraus, 



Sceloporns biserJatiis, Crotah;s lucifer, 



Sceloporus magister, Crotalus tigris, 



Pbrynosoma platyrhinos, Crotalus cerastes. 



Many kinds of reptiles vary so much that it is diffi- 

 cult to find two specimens which are alike in color and 

 squamation. Sometimes the variations correspond with 

 definite geographical areas, as in the case of Cnemidoph- 

 orits tigrw and G. t. undulatus or Fhrynosoma blain- 

 villii and P. frontale, but more frequently they are 

 purely individual, as in Charina and many species of 

 Thamnophis. Many reptiles are subject to chameleonic 

 changes, or changes in accordance with the intensity of 

 the light, or with the colors of objects by which they 

 are surrounded. For these reasons the collector should 

 strive to secure many specimens of each species. 



Reptiles are to be found in all sorts of situations. 

 The collector should study their habits if he would be 

 successful in his search. Some kinds prefer moist 

 places, while others are most abundant on barren hill- 

 sides or on the open desert. As a rule, reptiles like 

 sunlight and warmth, but some species live in the 

 thicker forests, and not a few are nocturnal. 



Some reptiles may be caught with the hands unaided 

 by any apparatus. Other species, too agile to be cap- 



