678 CASTORID^— CASTOR 



British species is C. veterior, Lankester, from the Red Crag of Suffolk 

 (Pliocene). In this, certain of the enamel folds of the molars are 

 reduced to " islets " sooner than in C. fiber, and the premolars appear to 

 have been relatively larger. In these characters this species makes 

 some approach towards Trogontheriuni} Jaws of another species, 

 C. plicidens, Forsyth Major, first described from the Pliocene of the 

 Val d'Arno, have been found in the Norfolk Forest Bed. This species 

 is characterised by its broader incisors, slightly larger cheek-teeth, and 

 especially by "the complex and elegant plication" of the enamel of 

 the molars.^ 



Description: — The Beaver is a large heavily-built animal (head 

 and body, 820; tail, 380; hind foot, 170), with a rounded water-rat-like 

 head, short, heavy limbs, and remarkably modified tail. The upper lip 

 is not cleft, and the nostrils are separated by a broad, naked pad. The 

 eyes and ears are small : the latter are rounded, with little trace of 

 tragus or antitragus, densely clad with hair within and without, and 

 almost buried in the fur. The hands are relatively short but quite 

 broad ; their palms are naked, and for the greater part occupied by a 

 pair of large, rounded pads, which fuse centrally and represent the 

 posterior carpal pads of other rodents ; there is little distinct trace of 

 the anterior pads normally present ; the digits, of which 3 and 4 

 are the longest, are short and armed with long, slightly curved, and 

 rather flattened claws. The well-developed thumb bears a claw like 

 those of the fingers. The feet are very large, about two and a half times 

 as long as the hands, with broad, naked, scaly, and wrinkled soles, 

 the pads being practically obsolete ; each has five long toes, united 

 by a strong web which extends to the bases of the claws ; the latter 

 are in general like those of the hand, but are especially large on 

 digits 3 and 4 ; the claw of digit 2 is " double," a peculiar laterally 

 compressed supplement springing from the ball of the toe beneath the 

 claw proper and rivalling the latter in size ; digit 4 is the longest, 

 slightly exceeding 3 and 5. The tail is of exceptional strength, and 

 highly modified as a swimming and steering organ ; it is very broad 



the summer of 1893, and so exposing the entrances to the burrows in the banks, were 

 purchased by the Zoological Society of London ; of them six lived for some time in 

 the Gardens at Regent's Park (^Proc. Zool. Soc, 1893, 612). Cocks informs us that 

 these would not eat the rations usually supplied to the Canadian Beavers. Cocks 

 has further kindly called our attention to a paragraph in the Times (30th December 

 1913), stating that a local sportsman had killed a Beaver near Dijon. If this 

 example does not point to the existence of an inland colony, previously overlooked, 

 then it must have followed the Rhone, and its continuation the Saone, for more than 

 half the length of France. 



^ Lankester, Ann. Mag: Nat. Hist., 1864, 355 ; Newton, Pliocene Vert, 1891, Jo; 

 and Hinton, Ann. Mag. Nat. Hist., January 1914, 186. 



2 Forsyth Major, P.Z.S., 1908, 630; Hinton, Ann. Mag. Nat. Hist., January 

 1914, 188. 



