THE AMERICAN FAUNA AND ITS ORIGIN. 
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species in South America. The glutton or wolverine, Gulo 
luscus, is restricted to the cold regions of the north of both the 
Old and New World, hut in America it comes as far south as 
Lake Superior. Of the Ursidse or bears, the most abundant is 
the grizzly bear of the Rocky Mountains, Ursus horribilis, 
which is closely related to the common brown bear of Europe, 
while the spectacled bear, Ursus ornatus, is restricted to the 
Andes of South America. The great white bear, Thalassarctos, 
or polar bear, Ursus maritimus, is, of course, confined to the 
Arctic coasts of the continent. 
Of the order Ungulata there is a somewhat remarkable 
representation in America. The three conspicuous ungulates 
of the Old World, the horse, the ass, and the pig, are wanting, 
and the sheep is only represented by the bighorn, Ovis 
canadensis, of the north-west mountains, while the tapirs have 
four out of six species in the Neotropical region. The 
reindeer, Rangifcr tarandus, of America differs somewhat from 
the reindeer of the Balaearctic region, as was explained in my 
paper on the fauna of Europe, and it ranges further south. In 
Labrador, the caribou, as it is called, may be found in herds of 
thousands. The elk or moose deer, Alces machlis, ranges south- 
wards from the Arctic coasts to 45° N. latitude. The Bovidae 
are not at all represented in the Neotropical region, being 
confined to North America, where the bison until recently was 
in countless numbers on its great prairie lands. 
The musk ox, Ovibos moschatus, partakes of the character of 
both the ox and the sheep of Europe, but it is confined to the 
barren grounds, or great desert regions of the extreme 
north of the continent bordering the Arctic coasts. The 
prongbuck, Antilocarpa americana, is also confined to North 
America, but to the more southern latitudes of the prairies. 
The mountain goat, Haploceros montanus, seems to be confined 
to the northern parts of California. The American ungulates 
of the family Camelidse are the llamas and the alpacas that 
form the four species of the genus Auchenia. These are 
entirely confined to South America. 
The rodents, which number as many as 159 genera and 1,400 
species, are largely represented in America, and no less than 
five families of the order Rodentia are not to be found in any 
other part of the world. These are the pouched rats, the 
haploodons, the chinchillas, the arboreal porcupines, and the 
guinea-pigs. The very widespread and well known family of 
Murid ae, with 87 genera and 730 species of rats and mice and their 
congeners, has many genera well represented in America, both 
