48 THE AMERICAN BEAVER. 



The body of the beaver is largest at its centre, and 

 diminishes in size toward each extremity. The ani- 

 mal has a ratlike appearance about the head and neck, 

 and the smallness of the eyes and ears renders its phys- 

 iognomy dull and uninteresting. The body is covered 

 with reddish-brown hairof two kinds : the longer coarse 

 hairs are about 2" in length and t5o " in diameter, and 

 the shorter, which are of a lighter color, and partly 

 concealed by the former, are about 1" long, and ttW 

 in diameter. Both kinds present an imbricate epi- 

 dermoid structure. The beaver has the peculiar 

 odor of the castoreum, to be hereafter described. Its 

 head is rounded, flattened above, and the muzzle is 

 somewhat prominent. The upper lip is emarginate 

 to the edge of the incisor gum, where it closely ad- 

 heres. The lower lip is loose and pendant, so that 

 the incisor teeth are prominent features. Both lips 

 are somewhat drawn in behind the incisors, and are 

 slightly hairy within. From the angle of the mouth 

 a thin line of hairs extends backward one-fourth of 

 an inch to a quadrangular patch of thickly set hairs 

 on the inside of the cheek, 80'" in length and 32'" in 

 breadth. From the emarginate upper lip (in one 

 beaver) the hair extends 66'" to the naked muffle, 

 which is 90'" long and 22'" broad, covered with rough 

 black epidermis. In two beavers the naked portion 

 of the muffle includes the nostrils, and extends in a 

 narrow line to the edge of the lip. The nostrils are 

 lateral, hairy, round when expanded, and assume a 

 sub-triangular or crescentic form, the convexity being 

 in front. Width between nostrils in one, 75'", in an- 

 other, 66'"; diameter of nostrils, 20'". There are five 

 rows of bristles, the upper row having but few hairs. 



