948 



RODENTIA 



1833. Castor proprius Billberg, Linn. Samf., p. 3i footnote (Substitute for 

 fiber). 



1857. Castor fiber Blasius, Saugethiere Deutschlands, p. 405. 



1897. Castor fiber CoUett, Bergens Museums Aarbog, pp. 3-127. Habits in 

 Norway. 



1907. Castor albicus Matschie, Sitz.-Ber. Gesellsch. Naturforsch. Freunde, 

 Berlin, p. 216, October, 1907. (Dessau, Anhalt, Germany.) See 

 Lonnberg, Arkiv for Zoologi, v, no. 6, pp. 1-16, 1909. 



1907. ? Castor vistulinus Matschie, Sitz. - Ber. Gesellsch. Naturforsch. 

 Freunde, Berlin, p. 219, October, 1907 (westei-n Poland). 



1910. Castor fiber Trouessart, Faune Mamm. d'Europe, p. 130. 



Tijpe locality. — Sweden. 



Geographical distribiition. — Formerly the entire forested region 

 of Europe, west to Great Britain ; now exterminated eve j"y where 

 except in portions of Scandinavia, and along the courses of some 

 of the larger rivers of central Europe, as the Rhone, Elbe, and 

 Danube. 



Diagnosis. — General features as in the family and genus ; 

 posterior extremity of nasals lying at or slightly behind level 

 of middle of orbit and decidedly behind termination of na.sal 

 branches of premaxillaries ; least depth of rostrum behind incisors 

 not equal to distance from gnathion to anteorbital foramen. 



External characters. — General form heavy and thick-set, the 

 head large and rounded, the eyes and ears small, the legs short, 

 the feet large ; the tail somewhat less than half as long as 

 head and body, its width about one-third its length. Head 

 short, deep and rounded, the eye small, about midway between 

 ear and nostril ; ear low and rovmded, densely haired on both 

 surfaces, scarcely appearing above the surrounding fur ; meatus 

 small but apparently without any specially developed valves ; 

 muzzle pad mostly naked, but with fur encroaching on its 

 posterior border and along inner margin of nostril ; below pad 

 the lip is less densely haired than elsewhere, and the hairs tend 

 to converge along median line ; whiskers very coarse and bristly, 

 the longest extending a little beyond eye when laid back. Front 

 foot with no special peculiarities, the digits all well-developed, 

 with strong, little curved claws, the thumb shorter than the 

 other digits but armed with a large claw somewhat more curved 

 than the others ; palmar tubercles five, the three at bases of 

 median digits large, ill-defined, that at base of thumb not so 

 large as the others but better defined, its outer surface tending 

 to become smooth and horny, the posterior pad largest, covering 

 about one-third of entire palmar area ; surface of pads (except 

 as otherwise described) coarsely reticulate. Hind foot very 

 large and broad, the digits united by a web extending to base 

 of claws ; second and third digits equal and longest, their 

 claws heavy, scarcely concave on lower surface, considerably 

 larger than those of other toes ; first, fourth, and fifth toes 

 successively shorter than second and third, their claws smaller 



