Feb., 191 2. Mammals of Illinois and Wisconsin — Cory. 159 



Genus CASTOR Linn. 



Castor Linnaeus, Syst. Nat., X ed., I, 1758, p. 58. Type Castor fiber 

 Linn. Characters as given for the family. 



Dental formula: I. , C. > Pm. , M.~ ^^=20. 



i-i 0-0 i-i 3-3 



Castor canadensis Kuhl. 

 Beaver. Canadian Beaver. 



Castor canadensis Kuhl, Beitr. z. Zool., 1820, p. 64. Osborn, Annals of Iowa, 3rd 

 ser., VI, No. 8, 1905, p. 566 (Iowa). Adams, Rept. State Board Geol. Surv. 

 Mich., 1905 (1906), p. 129 (Michigan). Jackson, Bull. Wis. Nat. Hist. Soc, 

 VI, 1908, p. 19 (Wisconsin). Hollister, Bull. Wis. Nat. Hist. Soc, VI, 1908, 

 p. 139 (Wisconsin). 



Castor fiber Kennicott, Trans. 111. State Agr. Soc, I, 1853-54 (1855), p. 579 (Cook 

 Co., Illinois). Lapham, Trans. Wis. State Agr. Soc, 1852 (1853), p. 339 (Wis- 

 consin). Allen, Proc Bost. Soc. Nat. Hist., XIII, 1869 (1871), p. 190 (Iowa). 

 Osborn, Proc. Iowa Acad. Sci., I, 1887-89 (1890), p. 43 (Iowa). Herrick, 

 Geol. & Nat. Hist. Surv. Min., Bull. No. 7, 1892, p. 170 (Minnesota). Ever- 

 MANN & Butler, Proc. Ind. Acad. Sci., 1893 (1894), p. 128 (Indiana). 



Castor Canadensis Thomas, Trans. 111. State Agr. Soc, IV, 1859-60 (1861), p. 657 

 (Illinois). Miles, Rept. Geol. Surv. Mich., I, i860 (1861), p. 221 (Michigan). 

 Hoy, Trans. Wis. Acad. Sci. Arts & Letters, V, 1882, p. 256 (Wisconsin). Wood, 

 Bull. 111. State Lab. Nat Hist., VIII, 1910, p. 536 (Illinois). 



Type locality — Hudson Bay. 



Distribution — North America, from about latitude 40° northward to 

 Labrador and Hudson Bay region and in the western portion of its 

 range to the Arctic Circle; replaced in the South and extreme West, 

 about longitude 120°, by slightly different geographical races. 



Description — General color brown ; the hairs on upper parts dark 

 brown at base, tipped with lighter brown or chestnut; under parts 

 paler than the back ; sides of neck and rump light cinnamon brown ; 

 tail flat and rounded (paddle shaped), black, and covered with 

 scales; claw on second toe of hind foot double or divided. 



Measurements — Total length, about 42 in. (1068 mm.); tail, 16.25 

 in. (410 mm.); hind foot, 6.75 in. (175 mm.). The bare, scaly part 

 of the tail measures about 9 inches long, 4.50 inches wide, and 1.50 

 inches in thickness in the middle. 

 Beavers were formerly common throughout Illinois and Wisconsin, 



but at the present time they are practically exterminated in the 



former state. Unfortunately we do not know precisely what form 



occurred in southern Illinois and lack of material for examination ren- 



