EXTERNAL CHARACTERS. 29 



Iii respect to the niystacial bristles, Dr. Murie's figures of the 

 head and muzzle of the young specimen described by him 

 (drawn from photographs, some from, the living animal) rep- 

 resent them as quite long, the longest being said to be from 4 to 

 5 inches hi length, and those of the sides of the muzzle as curv- 

 ing inward and nearly meeting beneath the chin. Lament also 

 speaks of them as being in the adult 6 inches in length. Ham- 

 ilton describes the Orkney specimen as having the largest 

 nearly 5 inches in length, "and as thick as a Thrush's quill." 

 Dr. Kane says : " Tlie cheeks and lips are completely masked by 

 the heavy quill-like bristles." The authors of the history of the 

 Swedish expedition to Spitsbergen and Bear Island in 1861 

 state that they are 4 inches long and nearly a line thick.* In 

 the four or five adult male specimens I have had the opportu- 

 nity of examining, the exserted portions of the longest bristles 

 were less than 3 inches in length, and when extracted measured 

 scarcely more than 4i, the shortest being mere points projecting 

 through the skin. From Dr. Murie's figures and description of 

 the young, and from other accounts, it would seem, that the 

 bristles become shorter in adult life, being perhaps worn off 

 by constant friction. The bristles in the specimens I have seen 

 bore no resemblance to the long curving bristles figured and 

 described by Dr. Murie as existing in the young animal. They 

 were considerably (one-third) longer, however, in the youngest 

 of four specimens in Professor Ward's collection than in the 

 oldest, giving support to the opinion already stated that they 

 become shorter as the annual advances in age.t 



As already noted, the fore feet are formed much as in other 

 Pinnipeds, more nearly agreeing, however, with those of the 

 Otarlidce than with those of the Phocidce, especially with respect 

 to freedom of movement, having the power of pronation and 

 supination to a considerable degree. " In the Walrus," says Dr. 

 Murie, "the humerus, radius, and ulna can be so placed that 

 they meet at an acute angle, the lower limb of which is in a 

 great measure free. The digits, on the other hand, can together 

 be turned backwards at a sharp angle with the radius and ulna, 

 so that the bones of the limbs altogether form an S -shaped 

 figure. In the Seal the antibrachium and digits bend on each 



* See Passarge's German translation, p. 132. 



tin Pallas's figure (in his "Icoues") of a young example of the Pacific Wal- 

 rus, the mystacial bristles are represented as very long, as in the young of 

 the Atlantic species. 



