342 DISAPPEARANCE OF HAIR chap. 



by a few hairs only — so few that they can be counted with ease 

 — in the neighbourhood of the muzzle. These hairs are not 

 present in all Whales ; they are absent, for example, in the White 

 AVhale or Beluga. When present they are not furnished either with 

 sebaceous glands or with muscular fibres, which are such universal 

 concomitants of the hair follicles in the Mammalia generally. 

 This appears to be conclusive evidence that the hairs, few as they 

 are, are still undergoing degeneration. The need for a furry 

 coat is removed by the presence of a thick coating of fat im- 

 mediately underlying the skin. This is known as the blubber, 

 and is the main incentive to the pursuit of Whales. It must 

 not, however, be assumed without further argument that the hair 

 is absent because its place is taken, as a mechanism for retaining the 

 heat, liy the blubber ; for the Seal tribe possess both fur and blubber. 

 Another conceivable explanation is quite at variance with such a 

 view of economy. It may be noticed that among Ungulates there 

 is a tendency to lose hair, particularly among more or less aquatic 

 forms. Thus the Hippopotamus is almost naked (as is indeed the 

 Walrus) ; the Rhinoceros, too, often a frequenter of marshy soil, is 

 almost as denuded as is the Hippopotamus. It is not, however, 

 settled that the Whales have anything to do with the Ungulata ; 

 otherwise an additional argument might be used, that is, the 

 secular loss of hair in some members of this group. The Hairy 

 Ehinoceros, Rh. ticJiorhinus, was, as its name denotes, a hairy 

 beast ; the Mammoth was equally so. The descendants, or at 

 least the modern representatives of both these creatures, are but 

 scantily clad with hairs. 



A final reason for the naked character of the skin in exist- 

 ing Cetacea is closely connected with a feature in the organisa- 

 tion of three or four living species which must first be 

 described. 



Some years ago the late Dr. J. E. Gray of the British Museum 

 described from the sea, off Margate, what he considered to be a 

 new species of Porpoise, characterised by the presence on the 

 dorsal fin of a row of stony tubercles. As a matter of fact it 

 was subsequently shown that the Common Porpoise has the same 

 structures, so that there was no need for a Margate species, 

 Fhocaena tiibeyxulifera. Moreover, in the Indian Neomeris, a 

 close ally of the Porpoise, a more abundant calcified covering of 

 scales exists along the whole back of the animal. These plates, 



