1922] Schmidt, Amphibians and Reptiles of Lower California 621 



the discussion; but the two insular species of Sator, which is not repre- 

 sented on the peninsula, may be mentioned in this connection, especially 

 as Sator is the only genus of reptiles entirely confined to Lower California 

 (cf. Verticaria, etc., above). 



Of the species occurring outside the Cape district, only Natrix 

 valida and possibly Gerrhonotus multi-carinata (cf. Stejneger and Barbour, 

 1917, p. 61) are West Mexican and not found in northern Lower Cali- 

 fornia, although Ctenosaura hemilopha, Bipes biporus, and possibly 

 Elophe rosalise are most closely allied to West Mexican forms at present. 

 The relations of the San Lucan fauna with the San Diegan and the 

 Colorado Desert faunae are very unequal. 



Of the fifty-two species, fifteen occur also in the Colorado Desert fauna 

 and seven more are obviously closely allied to Colorado Desert forms; 

 ten are identical with San Diegan forms, but of these, two are found 

 also in the desert; while five more species are more closely allied to San 

 Diegan forms than to desert forms; the proportion of Colorado Desert 

 element to San Diegan element is therefore about 22 to 13. The San 

 Lucan forms in the San Diegan district, however, appear to be largely 

 derived forms, as with the exception of Hyla regilla, Plestiodon skil- 

 tonianus, and Rhinocheilus lecontei, these find their northern limit in this 

 area, while the San Lucan forms which reach the desert for the most 

 part (generically if not specifically) have a wide range. This I have 

 shown more fully above in discussing generic ranges. 



Sax Lucan Species Occurring in the Colorado Desert or Allied Sonoran 



Faunae 

 (a). As Identical Species 

 Scaphiopus couchii Siagonodon humilis 



Bufo punctatus Coluber flagellum piceus 



Phyllodactylus tuberculosus Salvadora hexalepis 



Crotaphytus collaris baileyi Phyllorhynchus decurtatus 



Crotaphytus wislizenii Sonora episcopa 



Callisaurus ventralis gabbii Chilomenisms cinctus 



Uta mearnsi Trimorphodon lyrophanes 



Crotalus mitchellii 



(b). As Related Species 

 San Lucan • Colorado Desert 



Dipso-saurus dorsalis hicasensis Dipso-saurus dorsalis dorsalis 



Sauromalus ater Sauromalus obesus 



Sceloporus zosteromus Sceloporus magister 



Uta elegans Uta stansburiana slejnegeri 



Xantnsia gilberti Xantusia vigilis 



Tantilla planiceps Tantilla nigriceps 



Crotalus atrox lucasensis Crotalus atrox atrox 



