356 0. C. Marsh— Vertebrate Life in America. 
There are two species, one about as large as a Tapir, and the 
other nearly twice that size. This genus is the type of a dis- 
tinct family, the Moropodide. In the lower Pliocene above, 
well preserved remains of Kdentates of very large size have 
been found at several widely separated localities in Idaho and 
capes These belong to the genus Morothertum, of hich 
two species are known. Last of the Rocky Mountains, i in the 
later fossils corresponds nearly with beds in Europe that have 
been called Miocene. In the Post-Pliocene of North America, 
is ace by the huge Mylodon, ae Megalonyz, 
ren ie Ochotherium, Gnathopis, Lestodon, Scelidotherium, and 
Sphaenodon ; and among the A phniilison were Chlamydotherium, 
Hurydon on, Gly jptodon, Heterodon, Pachytherium and Schistopleurum. 
Peraiherim, another extinct genus, is supposed to be allied 
to the Ant-eaters, 
It is frequently asserted, and very generally believed, aie pi 
large number of huge Edentata which lived in North Am 
during the Post-Phocene, were the results of an onteserts 
migration from South America soon: after the elevation of 
the Isthmus of Panama, near the close of the Tertiary. fe) 
conclusive proof such migration has been offered, and 
the evidence, it seems to me, so far as we now it, 1s 
? 
on ppnores. to this view. No undoubted Tertiary Edentates 
een discovered in South America, while we have at 
iat i species in our Miocene, and during’ na ehageie. of 
our lower Pliocene, large individuals of this oup 
uncommon as far north as the forty-third puttallel of latitude, 
on both sides of the Rocky Mountains. In view of these facts, 
and others which I shall lay before you, it seems more natural 
to conclude from our present knowledge, that the migration, 
which no doubt took place, was from north to south. The 
Edentates finding thus in South America a congenial home 
flourished greatly for a time, and although the larger forms are 
now all extinct, diminutive representatives of the group still 
inhabit the same region 
The Cetacea first appear in the Eocene, as in Europe, and 
