370 O. C. Marsh— Vertebrate Life in America. 
by several species of Canzs, or a very nearly allied form. The 
peculiar genus Hycenodon, found also in Europe, and the type of 
a distinct family, is abundant in the Miocene east of the Rocky 
Mountains, but has not yet been found on the Pacific Coast. 
In the Pliocene of both regions; the Canide are numerous, 
and all apparently belong to the existing genus-Canis. The 
genus Machairodus is still the dominant form of the Cats, which 
are abundant, and for the most part belong to the genus Felis. 
The extinct Leptarctus is supposed to belong to the Urside, 
and if so, is the oldest American representative of this family. 
In the Post-Pliocene, the extinct Melide include species nearly 
as large as a lion, and smaller forms very similar to those still 
living. Bears, Raccoons and Weasels have also been found. 
n the Pliocene of South America, Machairodus represents 
the Felide, while the genera Arctotherium and Hycnarctus 
belong to the Bear family. Species of Mustela and Canis have 
also been found. In the caves of Brazil, the fauna of which 
is regarded as Post-Pliocene, one species of Macharrodus is 
nown, and one of Synelurus. Canis and J/eticyon, still living 
in Brazil, and the extinct genus Speothos, represent the Canidae. 
Mephitis and Galictis, among the Weasels, were also present, 
and with them species of Nasuwa and Arctotherium. 
e come now to the highest group of Mammals, the Pri- 
mates, which includes the Lemurs, the Apes, and Man. is 
order has a great antiquity, and even at the base of the Eocene 
we find it represented by several genera belonging to the lower 
forms of the group. In considering these interesting fossils, it is 
important to have in mind that the Lemurs, which are usually 
oe as Primates, although at the bottom of the scale, are 
only found at the present day in Madagascar and the adjacent 
regions of the globe. the American Monkeys, moreover, 
belong to one group, much above the Lemurs, while the Old 
World Apes are higher still, and most nearly approach Man. 
In the lower Eocene of New Mexico, we find a few repre- 
sentatives of the earliest known Primates, and among them are 
the genera Lemuravus and Limnotherium, each the type of a 
distinct family. These genera became very abundant in the 
middle Eocene of the West, and with them are found many 
others, all however, included in the two families, Lemuravide 
and Limnotheride. Lemuravus appears to have been most 
nearly allied to the Lemurs, and is the most generalized form 
of the Primates yet discovered. It had forty-four teeth, form- 
ing a continuous series above and below. The brain was 
nearly smooth, and of moderate size. The skeleton most 
resembles that of the Lemurs. A nearly allied genus, belong- 
ing to the same family, is Hyopsodus. Limnotherium (Tomithe- 
rium) also is nearly related to the Lemurs, but shows some affin- 
