LEMMING AND AKCTIC HAKE 9 



remains which have been discovered in caves and other super- 

 ficial (Pleistocene) deposits in Pennsylvania, Kentucky, Mis- 

 souri, Iowa and Ohio may have belonged to varieties of Ovibos 

 moschatus rather than to extinct species of musk oxen. 



There are two other arctic mammals which are of special 

 interest to us, since both of them inhabit Greenland. They 

 are the arctic hare (Lepus variabilis = L. timidus) and the arctic 

 lemming (Dicrostonyx torqnatus = Cuniculus torquatus). 



Like the reindeer, the arctic hare is subject to great varia- 

 tion over the vast area which it inhabits, and some of these 

 varieties or races are now recognised by many zoologists as 

 species. Mr. R. Brown * long ago felt the difficulty, nay, 

 almost impossibility, in discriminating between the Green- 

 land hare and the arctic or varying hare of Europe. The same 

 embarrassment has confronted many subsequent authors. In 

 American-he Greenland hare is now generally considered as 

 specifically distinct from the arctic American hare, Mr. 

 Rhoads f having pointed out some important features in its 

 incisor teeth, while Mr. Nelson J finds that its excessively 

 heavy wool -like coat of fur, the long claws and tapering upper 

 mandible sufficiently distinguish it from its relatives on the 

 American Continent to give it the rank of separate species. 

 However, as Mr. Rhoads aptly remarks (p. 356) the peculiar 

 dentition, long fur, and long claws are due partly to the 

 scantiness and character of plant life, and partly to the depth 

 and long continuance of the snow in Greenland. These fea- 

 tures seem to have gradually impressed themselves on the 

 Greenland hare in modifying it in the direction indicated. 

 In Major Barrett-Hamilton's opinion the chief differences 

 between the European arctic hares and the Greenland form, 

 from an external point of view, are only of a su|b- specific 

 value, while Dr. Winge || does not specifically distinguish the 

 American or European arctic hares from the Greenland one. 

 The same problem of affinity has recently been investigated 

 from a new standpoint by Mr. Hinton. His researches have 



* Brown, R., " Mammals of Greenland," p. 351. 



t Rhoads, S. N., u Polar Hares of North America," p. 368. 



| Nelson, E. W., " Rabbits of North America," p. 68. 



Barrett-Hamilton, G. E. H., " The Variable Hare," p. 92. 



|| Winge, H., " Gronlands Pattedyr," p. 376. 



