438 General Notes. | (July, 
These early Primates appear to be related both to the lemurs of the 
Old World, and to some of the South American monkeys. Two families 
are known, the Lemuravide, from Lemuravus,the principal genus, which 
has forty-four teeth, and the Limnotheride, which have not more than 
forty. The latter group is rich in genera and species. Among the 
other Eocene mammals discovered were marsupials and bats, not before 
known in a fossil state in this country. One of the most important 
Eocene mammals found was a small ungulate, which is the oldest proba- 
ble ancestor of the horse. It was about as large as a fox, and had four 
es 
others from the later tertiary, enabled Professor Marsh tọ trace the line 
of descent which has apparently produced the modern horse. In addi- 
tion to the Eocene mammals, many species of birds, serpents, lizards, and 
other vertebrates were collected. 
The discoveries made by the same expeditions in the Miocene and 
Pliocene lake-basins of the Rocky Mountains and Pacific coast were 
likewise very numerous, and many new forms of animal life were brought 
to light. One group of mammals found in the early Miocene of Oregon 
is allied to the modern Rhinoceros, but differs in having a transverse pair 
of horn-cores on the nasal bones. The genus was called Diceratherium, 
and one of its species is the oldest known member of the Rhinoceros 
family, if not its progenitor. The most remarkable mammals found in 
the Miocene were the huge Brontotheride, which are apparently allied 
both to the above group and to the Eocene Dinocerata. They equ ed 
the latter in size, and also had an elevated pair of horn-cores on the 
maxillary bones. One genus of this family was previously known bya 
few imperfect specimens. Besides Brontotherium, several other new 
genera of this group were found, represented by portions of over two 
hundred individuals. With these remains was discovered a genus y 
small equines, Mesohippus, about as large as a sheep, and having thee 
toes on each foot, with an additional “splint” bone on those in front, 
thus forming an interesting Miocene link in the genealogy of the horse, 
completed by the Pliocene genera. Over thirty species of fossil horses 
were collected in these formations. Among the interesting animals oF 
tained in the Pliocene deposits were two species of large Edentates, the 
first tertiary representatives of this order from America. They belong 
to a new genus, Morotherium. There were also found large numbers 
thinoceroses, camels, Suillines, and other mammals, as well as many 
birds, reptiles, and fishes. . 
A study of the large series of extinct animals thus collected, and now 
in the Yale Museum, promises to throw much light on the development 
of life on this continent, and Professor Marsh has already drawn 1 
them some important principles. One of these relates to the size 
growth of the brain in mammals, from the beginning of the Tertiary 1° 
