Vol. XXIX, pp. 21-24 February 24, 1916 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



APLODONTIA HUMBOLDTIANA, A NEW MOUNTAIN 



BEAVER FROM THE HUMBOLDT BAY 



DISTRICT, CALIFORNIA. 



BY WALTER P. TAYLOR. 



[Contribution from the Museum of Vertebrate Zoology of the University of California.] 



The range of the genus Aplodontia within California embraces 

 three areas : The Cascade-Sierra Nevada mountain system from 

 the northern boundary of the State south at least to Mammoth, 

 Mono County ; the Trinity-Siskiyou mountain mass in the ex- 

 treme northern part of the State ; and the coast district from 

 the northern boundary of the State south to San Francisco Bay. 

 Two coast forms have already been described : Aplodontia phasa 

 Merriam, from Point Reyes, Marin County, and Aplodontia nigra 

 Taylor, from Point Arena, Mendocino County. It has been 

 known for some time that another form of Aplodontia occurs in 

 the Humboldt Bay district, but lack of adequate material for 

 description and comparison has postponed the decision of its 

 systematic status till now. The writer desires to express his 

 thanks to the authorities of the Field Museum of Natural His- 

 tory, and particularly to Mr. Wilfred H. Osgood, Assistant 

 Curator of Mammalogy and Ornithology, for the loan of speci- 

 mens for study. 



Aplodontia hutnboldtiana new species. 



T(/pe.— Male adult, No. 21,162, Mus. Vert. Zool.; Carlotta, Humboldt 

 County, California; January 4, 1914; collected by H. E. Wilder; Orig. 

 No. 1494; stuffed skin, with skull and jaws, all in good condition. 



Diagnosis. — Similar in coloration to Aplodontia chryseola, but darker; 

 paler hue of brown series of colors interspersed with black hairs ; ventral 

 brown wash much less distinct. Skulls may usually be separated from 



6— Proc. Biol. Soc. Wash., Vol. XXIX, 1916. (21) 



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