200 NEW YORK ZOOLOGICAL SOCIETY. 
THE DEER. 
In contrast to this probable African origin of the Bovidae, there 
is little doubt that the Cervidae, or deer family, achieved its 
development in Eurasia, with an important outlying group on 
this continent, which, springing from some early Eurasian ances- 
tor, developed into the American deer, Odocoileus. 
There are in America five genera of this family. The first 
two, the moose, Alces, and the caribou, Rangifer, are circumpolar 
in distribution. Being animals of large size and great endurance, 
they can and do make long migrations, the moose rarely and only 
when impelled by danger or failing food supply, and the caribou 
at regular intervals. It is consequently not surprising to find a 
close resemblance between the Old and New World species of 
each genus. 
Both the moose and caribou may have developed in some 
as yet unknown subarctic land. In fact these two genera seem to 
afford the only evidence from the fauna of North America in 
support of the theory of the boreal continent. Of the two, the 
caribou shows, in its structure, more adaptation to Arctic condi- 
tions. 
Of the American moose only two species are known, one of 
limited distribution in southern Alaska, A. gigas, and the other, 
A. americanus, ranging from the limit of tree growth in western 
and northern Alaska to Nova Scotia on the Atlantic coast, and 
just entering the United States at several points along its north- 
ern boundary. It is a larger and finer animal than its Eurasian 
relative. This, too, holds true of the caribou. 
We have in the American Pleistocene deposits a mooselike 
form known as Cervalces, with complex antlers which are highly 
suggestive of those of the giant Alaskan moose. This animal 
was Closely related and possibly ancestral to the moose, in which 
case the moose may have developed in the northern part of the 
continent and crossed into Eurasia. More probably it represents 
another and somewhat aberrant species of moose, coming in at 
the same time from northern Siberia or other boreal lands. 
In the genus Rangifer we have a greater variety of types, and 
the species fall naturally into two groups: barren ground caribou 
and woodland caribou. 
The first has five species: Fe. granti, of the Alaskan Peninsula on 
the west; FR. stonei, of the Kenai Peninsula and adjoining main- 
land (the handsomest of barren ground caribou) ; the typical R. 
