Vol. XXI, pp. 141-142 June 9, 1908 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



A NEW WHITE-FOOTED MOUSE FROM ALASKA. 

 BY WILFRED H. OSGOOD. 



In order to provide a name for immediate use in another con- 

 nection, the following brief description is published of a white- 

 footed mouse representing the form prevalent on most of the 

 islands of southeastern Alaska. Although material is now avail- 

 able from nearly all these islands, a few points still remain to be 

 cleared up regarding peculiarities of geographic distribution. 

 Certain well-marked forms apparently are confined to particular 

 islands while others, like the present one, show little or no dif- 

 ferentiation from island to island. Very little variation in color 

 appears among the several forms of the region and distinctions 

 rest mainly on dimensions and cranial characters. In order not 

 to anticipate unpublished results of a study of the large group 

 to which this form belongs, it is given full specific rank with 

 only limited discussion of relationships. 



Peromyscus hylaeus sp. nov. 



Type from Hollis, Kasaan Bay, Prince of Wales Island, Alaska. No. 

 127,038, U. S. National Museum, Biological Survey Collection. May 15, 

 1903. W. H. Osgood. 



Geographic distribution. — Islands and coast of southeastern Alaska west 

 and northwest of the range of P. macrorhinus including Prince of Wales, 

 Kupreanof, Mitkof, and Admiralty islands and the mainland coast from 

 Lynn Canal to Frederick Sound. 



Characters. — Most similar to P. keeni of the Queen Charlotte Islands, 

 but skull more lightly built with the rostrum longer and more slender ; size 

 decidedly less than in macrorhinus and sitkensis; color darker and ears 

 and tail shorter than in oreas. 



Color. — Practically as in keeni, macrorhinus, and other species of the 

 humid Pacific coast; sides varying from russet to Mars brown shading to 

 Mars brown and Prout Brown on the back ; underparts white ; tail sharply 

 bicolor. 



19— Proc. Biol. Soc. Wash., Vol. XXI, 1908. (141) 



