226 Field Museum of Natural History — Zoology, Vol. XL 



igan). Allen, Proc. Bost. Soc. Nat. Hist., XIII, 1869 (1871), p. 194 (Iowa). 

 OsBORN, Proc. Iowa Acad. Sci., I, 1887-89 (1890), p. 43 (Iowa). Brayton, 

 Geol. Surv. Ohio., IV, Pt. i, 1882, p. 153 (Illinois, etc.). Strong, Geol. Wis., 

 Surv. 1873-79, I, 1883, p. 439 (Wisconsin). Merriam, Mamm. Adirondack 

 Reg., 1886, p. 275. EvERMANN & Butler, Proc. Ind. Acad. Sci., 1893 (1894), 

 p. 126 (Indiana). Garman, Bull. Essex Inst., XXVI, 1894, p. 6 (Kentucky). 

 Rhoads, Proc. Acad. Nat. Sci. Phila., 1896 (1897), p. 186 (Tennessee). Miller, 

 Proc. Bost. Soc. Nat. Hist., XXVIII, 1897, p. 11 (North Shore, Lake Superior). 

 Snyder, Bull. Wis. Nat. Hist. Soc, II, 1902, p. 121 (Wisconsin). Adams, 

 Rept. State Board Geol. Surv. Mich., 1905 (1906), p. 129 (Michigan). Jackson, 

 Proc. Biol. Soc. Wash., XX, 1907, p. 73 (S. W. Missouri). McAtee, Proc. Biol. 

 Soc. Wash., XX, 1907, p. 5 (Munroe Co., Indiana). Hahn, Ann. Rept. Dept. 

 Geol. & Nat. Resources Ind., 1908 (1909), p. 517 (Indiana). Howell, Proc. 

 Biol. Soc. Wash., XXII, 1909, p. 62 (Tennessee, Mississippi, etc.). lb., XXIII, 

 1910, p. 29 (Illinois, Missouri, Kentucky). 



Type locality — Eastern Canada. 



Distribution — Eastern United States and southeastern Canada, south 

 to northern North CaroHna and northern Georgia and west to 

 eastern Nebraska and Kansas. Replaced farther west and in the 

 South by alhed forms. 



Description — General color dark chestnut brown above ; under parts 

 brownish white; fur of back and rump mixed with long, blackish 

 brown hairs; throat whitish; chin with brown spot; feet brown, the 

 claws horn color; tail black, nearly bare and flattened, vertically 

 being considerably higher than wide. Freaks of color often occtu*; 

 black specimens are not uncommon and partly white or entirely 

 white individuals are occasionally taken. 



Measurements — Size somewhat variable, generally 19 to 23 inches 

 long. The following measurements probably represent an average 

 specimen: Total length, 21.50 in. (546 mm.); tail vertebra, 10.50 

 in. (266 mm.); hind foot, 3.30 in. (86 mm.). 



Remarks — Cases of albinism, either complete or in part, are not un- 

 common. About three years ago Mr. W. S. McCrea of Chicago, 

 called my attention to a series of seven Muskrat skins from Hayfield, 

 Iowa, all of which were uniformly marked, having a white ring 

 around the neck and the entire under parts, feet and terminal portion 

 of tail white. Such uniform coloration in a series of specimens was 

 perplexing and suggestive, especially as they all came from the 

 same locality ; but later two specimens were received from Indiana, 

 which were similarly marked, but with the dark parts much paler. 

 The Field Museum collection contains a pure white example of this 

 species. 

 The Muskrat or "Musquash," as it is sometimes called, is common 



in the ponds, streams and overflowed marshes throughout Illinois and 



