Mexico weekly ledger., 1876-11-09

perissodactyle ungulates and the r
poscloea, may have been passed over.
Ihey were all elephant-like in bulk and
general appearance, yet presented a
complnatlOn OF characters which made
Lhem unlike any thing elsewhere known.
Ihelr feet were five-toed, their leps
straight and massive; their necks long-
er than the elephants, and their SIN Il.
orained, narrow head much more like
the r~hlnoceros's than the elephants,
put their distinguished peculiarity was
thelr frontal armament of three pairs of
horns, which, with their enormous size
ana strength, must have made them
formidable indeed. Their end is vet a
mystery. 1t has been suggested that at
the close of the eocene period they NAV
nave migrated to Asia to lay the founda-
ton of that family which first appears in
the old world under the more familiar
forms OF the typical proboscideans-the
elephants, mastodons, and mammoths.
Noneo OF these appear in America earlier
thar the pleiocene period, a long time
after they had become abundant in the
old world.
Among the carnivora which proved
upon the abundant herbivorous fauna
OF the great plains, forests, and lake
regions OF the tertiary ages, not a few
furnish extremely cogent evidence of
specific evolution. There were among
them fierce creatures, larger than
wolves (synaplotherum and mesonyx)
which presented such a combination of
characters that it is impossible to rank
them with either of the existing fami-
lies of the order to which they belong.
In some respects they were like dogs,
IN others they were bear-like; in still
others they were more generalized than
any existing members of the order.
Then there were several species of hye-
nodon, some larger than any of the
European forms, and others no larger
d a a fox; "the last survivors of q
group notably differing from any now
known" In the character of their
skulls they stand intermediate between
wolves and opossums. In the earlier
periods, still more generalized types
abounded. some of them combining
the generic characteristics of half q
dozen of Il specialized modern carni-
vOra.
Perhaps the most remarkable of these
comprehensive types was the tillodontia,
which seem to have combined the char
acteristics of several distinct Il
the carnivors, the hoofed animals, and
the rodents. Some of them were as
large as the tapir. Their molar teeth
were of the ungulate type, their CANNES
small, their incisors rodent-like. Their
heads were bear-like, their general
structure like that Of the ungulates,
their feet plantigrade. Two distinct
forms abounded: one in which the in
cisors grew from persistent pulps, like
the beavers, the other having all the
teeth rootless.
The dominant types of tertiary flesh
eaters, however, were various modifica-
lions of felida, fierce cats, some of them
surprising our modern lions and tigers
in size and strength. Chief among
them in the miocene age were the saber-
toothed tigers, which seem to have
overrun the whole world about that
time, and to have fingered in some parts
until the human period. 1t is one of
the puzzles of paleontology to account
for the extinction of this highly special
lied type, apparently the tittest of all
the cat family to win in the struggle for
existence. Happily for man they did
not survive in force,to contest his prog
ress toward the mastery of the earth.
Scientific american.