80 ONDATRA. 



Measurements. Total length, 59.4; tail, 185; hind foot, 66. Skull: 

 Occipito-nasal length, 60.7; Hensel, 55.6; zygomatic width, 38.3; 

 intertemporal width, 5.8; length of nasals, 20.9; breadth of nasals, 

 9.2; length of upper molar series, 14.4; length of mandible, 36.5; length 

 of lower molar series, 13.8. Ex type in United States National Museum . 



Ondatra zibethica mergens (Hollister). 



Fiber zibethica mergens Hollist., Proc. Biol. Soc. Wash., XXIII, 

 1910, p. i. 



Type locality. Fallen, Churchill County, Nevada. 



Geogr. Distr. Northern part of the Great Basin; southeastern 

 Oregon, northeastern California, Nevada, and western Utah. 



Gent. Char. Similar to O. osoyoosensis but paler; dorsal stripe 

 distinct. 



Color. Head blackish; cheeks rusty; upperparts grayish brown; 

 dorsal line blackish; shoulders and flanks rusty; blackish brown spot 

 on chin; underparts creamy white with a pale cinnamon central area. 

 Ex type in United States National Museum. 



Measurements. Total length, 540; tail, 240; hind foot, 70. 

 Skull: Occipito-nasal length, 60.7; Hensel, 58.4; zygomatic width, 

 40; intertemporal width, 6.7; length of nasals, 21; length of upper 

 molar series, 15.5; length of mandible, 32.3; length of lower molar 

 series, 14.9. Ex type in United States National Museum. 



Ondatra zibethica cinnamomina (Hollister) . 



Fiber zibethicus cinnamominus Hollist., Proc. Biol. Soc. Wash., 

 XXIII, 1910, p. 125. 



Type locality. Wakeeney, Trego County, Kansas. 



Geogr. Distr. Great Central Plains region of western United 

 States and Canada, from Manitoba south to northern Texas; east to 

 central Iowa, and west to the Rocky Mountains. 



Genl. Char. Smaller than F. zibethicus; color pale but more red- 

 dish. 



Color. Nose seal-brown; cheeks clay-color; upperparts and 

 flanks cinnamon-brown; dorsal region slightly darker; small brown 

 spot on chin; underparts from throat and inner side of limbs creamy 

 clay-color; tail dark brown; hands and feet drab. Ex type in United 

 States National Museum. 



Measurements. Total length, (skin), 436; tail, 190; hind foot, 

 45.4. Skull: Occipito-nasal length, 57.4; Hensel, 52; zygomatic 

 width, 34; intertemporal width, 6.07; palatal length, 35; length of 

 nasals, 19.5; length of upper molar series, 14.2; length of mandible, 

 angle to symphysis, 28.2; length of lower molar series, 14.5. Ex type 

 in United States National Museum. 



