HERPETOLOGY OF LOWER CALIFORNIA. 51 



There is in this area, as has already been shown, a 

 slight infusion of tropical forms, represented among rep- 

 tiles by the genera Ctenosaura and Euchirotes, but prob- 

 ably best illustrated by the plants growing near the coast 

 lagoons. These forms, however, are doubtless no more 

 numerous or characteristic than those forms, of tropical 

 origin, which will be found to intrude upon the entire 

 southern border of the Sonoran Subprovince. 



The northern part of Lower California is much more 

 closely related to the rest of the Sonoran Subprovince 

 than to the San Lucas Fauna. This is well shown by 

 the presence of such forms as Callisaurus ventralis, Cro- 

 taphytiis wislizenii, Phrynosoma solare, Rhinochilus le- 

 contei, and Cnetnidopkori of the tessellatus group. While 

 the known ranges of several species may be considerably 

 enlarged in the future, the northwestern part of Lower 

 California and the coastal slopes of San Diego (and Los 

 Angeles?) County, California, seem to be so well charac- 

 terized as to merit recognition as a distinct faunal area of 

 the lowest rank. Its distinctive features are the presence 

 of certain peculiar species, the absence of others occur- 

 ring near by, and its forming the limit of distribution of 

 species whose chief habitat is either north or south.* 



Pending further evidence, this area may be known as 

 the San Diegan Fauna, f Among the reptiles peculiar to 

 it may be mentioned the following :t 



*In this connection I have had the use of a large collection of the rep- 

 tiles of San Diego County, made by Messrs. Hyatt and Stoddard for the 

 Leland Stanford Junior University, as well as the specimens belonging to 

 the Academy. 



tWhen this was written the author was not aware that this area had 

 been previously recognized and mapped from study of other branches of 

 animal life. 



t Birds apparently belonging to the same list are Pipilo fuscus senicula, 

 Harporhynchus cinereus mearnsi, and Hdeodytes hruneicapillus hryanti. 

 2d Seb., Vol. V. ( 6 ) May 28, 1895. 



