178 



F. E. PEABODY AND J. M. SAVAGE 



the southern Sierra Nevada. Warm, dry trends of cHmate allowed 

 xeric elements to move north through mountain passes and into the 

 San Joaquin Valley and bordering foothills. 



Sympatry in Southern California 



Four cases of sympatry between closely allied forms occur in 

 southern California. Two of the four cases involve amphibians of 

 Arcto-Tertiary afTfinities; one of amphibians and one of reptiles are 

 of northern Madro-Tertiary affinities. The sympatry is not of the 

 same degree in each case, but it is sufficiently clear-cut to draw 

 attention to its localized occurrence in southern California. The high 

 incidence of sympatry here strongly suggests a controlling, historical 

 factor. It is believed that this factor is primarily the evolution of a 

 Coast Range corridor as outlined earlier. 



1. A classic rassenkreis of subspecies is represented by the dis- 

 tribution pattern of Ensatina eschscholtzii in California (Stebbins, 



^^^,ESCHSCHOLTZ'S 



SALAMANDER 

 ENSATINA 

 -^^ESCHSCHOLTZII 



XANTHOP 

 TICA' 



35 

 ESCHSCHOLTZII 



SYMPATRIC 



.V/;=INTERGRADE 



Fig. 15. Distribution of painted salamander, Ensatina eschscholtzii. 

 Subspecies E. e. eschscholtzii and E. e. klanberi occur together in upper 

 San Gorgonio River system, San Bernardino Mountains. 



