78 CALIFORNIA ACADEMY OF SCIENCES. 



of the Campestrian Subprovince on the north, or of the 

 tropical Central American Region on the south. They 

 need not, therefore, be considered in the present connec- 

 tion. Eleven genera remain which are confined to the 

 Sonoran Subprovince, and may be considered character- 

 istic of that area. These genera are : 



Dipsosaiirus, Sauromalus, Eena, 



Callisaurus, Heloderma, Lichauura, 



Holbrookia, Xantusia, Phyllorhyiichus. 



Uma, Verticaria, 



In the so-called Cape Region of Lower California, 

 twenty-eight genera of reptiles occur, namely: 



Phyllodactylus, - Cuemidophorus, Hypsiglena, 



Ctenosanra, Verticaria, Phyllorhynchus, 



Dipsosanrus, Enmeces, Salvadora, 



Crotaphytus, Euchirotes, Bascanion, 



Callisaurus, Rena, Pituopliis, 



Uta, Lichanura, Thamnophis, 



Sceloporus, Chilomeniscus, Natrix, 



Phrynosoma, Tantilla, Trimorphodou, 



Gerrhonotus, Lampropeltis, Crotalus. 

 Xautusia, 



Only two of these have not been obtained elsewhere in 

 the Sonoran Subprovince, while, with the exception of 

 Holbrookia, Uma, Sauromalus, and Heloderma, all the 

 characteristic Sonoran genera are represented. The two 

 Cape genera which have not been found in any other part 

 of the Sonoran Subprovince are Euchirotes, a two-footed 

 amphisb^nian which has been secured only in southern 

 Lower California, and Ctenosaura, a genus widely dis- 

 tributed in tropical America and here represented by a 

 single species. 



Considering now the species of these areas, it is found 

 that seventy -eight have been obtained in the Sonoran 

 Subprovince.* Twenty -one of these are of partly or 



*Some of the eastern and southern species have not been included for 

 lack of precise data. 



