Vol. XXIII, pp 125-126 September 2, 1910 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



A NEW MUSKRAT FROM THE GREAT PLAINS. 

 BY N. TIOLLISTER. 



Tlic muskrat of tlie (ircnt Plains region of the Avestorn United 

 States ])V(>\\'S to he one of tlie best characterized forms in the 

 groui). 



Fiber zibethicus cinnamominus snl)si). nuv. 



Tijife from Wakcvncy, Trego County, Kansas. No. |5|f Merriam 

 Collection. c? adult, skin and skull. Collected I)y A. P.. Baker, 

 January 14, 1SS7. 



General characters. — Smaller than Fiber z. zihet]iici(s or Fiber c. 

 osoi/ooxen,sis ; larger than F. z. ripensis. Coloration pale, with much 

 more reddish in hoth fresh and Avashed out pelage tlian any of these 

 forms. Skull smaller than that of zibethicus or osoyoosrnsis, with smaller 

 teeth. 



Color. — Fresh pelage: Upperparts and sides cinnamon brown, dorsal 

 area only sliglitly darker, with few black liairs. Nose to foreiiead and 

 eyes seal brown. Cheeks and underparts creamy clay coh^r, lighter on 

 neck, throat, and inner sides of legs. A very small brown spot on chin. 

 Feet drab; nails yellowish; tail dark brown. AVorn or washed out 

 pelage: A'arying from wood brown to russet. Specimens in the short- 

 haired early fall pelage are the darkest, and those in extreme faded early 

 summer coat are the lightest. 



Skull and teeth. — Skull smaller than that of Fiber z. zibethicua, Avith 

 smaller teeth ; larger than that of F. :. ripensis. Compared Avith skulls 

 of zibethicus it has a proi)ortionally shorter and heavier rostrum, accom- 

 panied by a shortening and widening of the nasals. 



Measureynents. — The type s])ecimen is without flesh measurements. 

 Two other specimens from the type locality measure: Total length, 

 4S9; 50:>; tail vertebrae, 287; 24:). AA'erage of hind foot in twenty-one 

 specimens from various localities on the Great Plains, 7:].o. Skull of 

 type: Basal length, 55. U (5(5.;))*; zygomatic breadth, 34 (35.5); palatal 



* Measureiiients in parenthesos arc the avcragos of five skulls of adults from the 

 type locality. 



;VJ— I'Kor. IJioi.. Sor. Wash., Vol.. .\XIII, 1910. (V-'.")) 



