Fes., 1912. MAMMALS OF ILLINOIS AND Wisconsin — Cory. 159 
Genus CASTOR Linn. 
Castor Linneus, Syst. Nat., X ed., I, 1758, p. 58. Type Castor jiber 
Linn. Characters as given for the family. 
Dental formula: I. eee pain =a Mi, 
fas o-o0 i=2 rae 
Castor canadensis Kuut. 
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). Apams, 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. III. 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). 
Osporn, 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 Tuomas, Trans. Ill. State Agr. Soc., IV, 1859-60 (1861), p. 657 
(Illinois). Mugs, Rept. Geol. Surv. Mich., I, 1860 (1861), p. 221 (Michigan). 
Hoy, Trans. Wis. Acad. Sci. Arts & Letters, V, 1882, p. 256 (Wisconsin). Woon, 
Bull. Ill. 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 Llinois 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- 
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