IX.] LIST OF THE FAUNA. 315 



north-western frontier of the Oriental region, while the single 

 North American form also enters the Sonoran. In a fossil state 

 it is possible that sheep occur in the Indian Siwaliks, but else- 

 where they are first known from the Forest-bed of the Norfolk 

 coast, belonging to the early part of the Plistocene epoch. More 

 nearly allied to the sheep than to the goats, the musk-ox (Ovibos) 

 of Arctic America is now extinct in the Old World, but as it is 

 abundant in the Plistocene of Europe and Asia, where it ranged as 

 far south as England, it is surely entitled to rank among the forms 

 common to the western and eastern halves of the Holarctic region. 

 Nearly allied extinct species occur in the Plistocene formations of 

 the United States. Among the Cervidce. there are three types 

 common to the entire region. The first, or Elaphine group, 

 includes the typical members of the genus Cervus, as represented 

 by the red deer (C. elaphus) of the Old World and the wapiti (C. 

 canadensis) of North America; this group being characterised, 

 among other features, by the general presence of both a brow- 

 and a bez-tine to the antlers, although the latter is wanting in 

 the North African variety of the red deer, and also in the Tibetan 

 C. thoroldi. The alliance between the wapiti and some of the 

 forms inhabiting Central Asia is so close as to render it doubtful 

 whether they are really anything more than varieties of a single 

 species. The single species of elk (Alces) is common to both 

 halves of the region ; and the same is also the case with the 

 reindeer (jRangtfer), which although now not found to the south 

 of Europe, ranged during the Plistocene era into the south of 

 France. The genera or groups which may be regarded as charac- 

 teristic of the entire Holarctic region may be tabulated as follows, 

 those which are practically peculiar being printed in italics : 



Insectivora. 



SORICID^E. Sorex. In America ranges into Sonoran. 

 TALPID^E. Urotrichus. Japan and N. America. 



Carnivora. 



FELID^E. Felis, the true lynxes solely Holarctic. 



MUSTELID.E. Latax. \ One species common to both 



Gulo. J hemispheres. 

 TRICHECHW&. Trichechus. 



