PROCEEDINGS 



OF THE 



CALIFORNIA ACADEMY OF SCIENCES 



Fourth Series 

 Vol. IV, pp. 153-160. December 30, 1914 



VI 



The Pocket Gopker of tke Boreal Zone 

 on San Jacinto Peak 



BY 



J. GRINNELL and H. S. SWARTH.* 



In our report upon the birds and mammals of the San 

 Jacinto area of southern California (Univ. Calif. Publ. Zool., 

 Vol. 10, 1913, pp. 354-355) the twelve specimens of pocket 

 gophers at that time available from the Boreal zone on San 

 Jacinto Peak were referred to Thomomys altivallis Rhoads. 

 That series contained not one adult male, and the possibility 

 was suggested that, upon proper comparisons, differences 

 would be found to exist whereby the species of San Jacinto 

 Peak could be distinguished from that of the San Bernardino 

 Mountains (altivallis). It will be recalled that the San 

 Jacinto and San Bernardino mountain masses are separated 

 only by the narrow, though deep, San Gorgonio Pass. The 

 latter is cut to such a depth as to be traversed by a tongue of 

 the Lower Sonoran zone, yet so steep are the confining walls 

 that the nearest limits of the boreal areas of the separated 

 mountain masses are only about seventeen miles apart. 



In order to clear up the relationships of the San Jacinto 

 gopher, opportunity w^as taken by the junior author, in Sep- 

 tember, 1914, to revisit San Jacinto Peak, with the result that 

 seven more specimens were obtained, four of which are adult 

 males. With this additional material we now find good 

 grounds for nomenclatural separation of the San Jacinto and 

 San Bernardino mountain gophers, and also for further dis- 

 cussion of relationships. 



^Contributed from the Museum of Vertebrate Zoology of the Uni- 

 versity of California. 



December 30, 1914 



