MICROTUS. 



ONDATRA. 79 



series, 5.8; length of mandible, 13.1; length of lower molar series, 5.8. 

 Ex type in American Museum of Natural History. 



Microtus intermedius Taylor. 



Microtus (Lagurus) intermedius Taylor, Univ. Calif. Publ. Zool., 

 VII, IQII, p. 253. 



Type locality. Head of Big Creek, Pine Forest Mountains, Hum- 

 boldt County, Nevada. Altitude 8000 feet. 



Subgenus E. Chilotus. 



Microtus oregoni adocetus Merriam. 



Microtus oregoni adocetus Merr., Proc. Biol. Soc. Wash., XXI, 1908, 



P- US- 

 Type locality. South Yolla Bolly Mountain, California. 



Genl. Char. Size large, ears small; skull like that of M. oregoni 

 but larger; rostrum longer; nasals and teeth larger. 



Color. Upperparts sepia to reddish sepia-brown; underparts 

 buffy plumbeous, under fur showing; tail above dark brown, beneath 

 paler; hands and feet whitish. Ex type in United States National 

 Museum. 



Measurements. Total length, 172; tail, 49; hind foot, 21. Skull: 

 Occipito-nasal length, 25.6; Hensel, 23.5; zygomatic width, 16; 

 intertemporal width, 4.2; length of nasals, 7.4; palatal length, 13; 

 length of upper molar series, 6; length of mandible, 16; length of 

 lower molar series, 6.4. Ex type in United States National Museum. 



Genus Ondatra. 



Ondatra zibethica zalophus (Hollister). 



Fiber zibethicus zalophus Hollist., Proc. Biol. Soc. Wash., XXIII, 

 1910, p. i. 



Type locality. Becharof Lake, Alaska. 



Geogr. Distr. Alaskan Peninsula, north to Nushagak and east 

 to the head of Cook Inlet. 



Genl. Char. Tail short; hind foot small, redder in color than 

 0. z. spatulata; molars small; zygomata less spreading anteriorly. 



Color. Upperparts bistre, darkest on hips; flanks with a tinge of 

 russet; underparts creamy white, washed with cinnamon; brown 

 streak on chin; lips whitish; throat white. Ex type in United States 

 National Museum. 



