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POPULAR SCIENCE REVIEW. 
ful existence in the deep shades of the tropical American 
forests, frequently become the victims of the ferocious jaguars 
and pumas, which prowl in search of prey through the rank 
vegetation of the river banks, or lie in wait concealed amid the 
luxuriant foliage of the branches overhead, it is only natural to 
suppose that the countless herds of tapir and swine-like herbi- 
vorous animals which lived in a similar manner amid the 
ancient Eocene swamps and forests of Wyoming and Colorado, 
were also destined to furnish subsistence to a tribe of rapacious 
beasts of form and fashion long passed away. Palaeontological 
research amply shows that this was the case. Side by side 
with the remains of Hyrachyus , Palceosyops , and the rest, are 
found bones and teeth of animals of various size and structure, 
but of undoubted carnivorous habits. Unfortunately at pre- 
sent most of these are known only by fragments, and not a few 
of the numerous genera recently described are founded on the 
evidence of a single tooth ! 
There are some, however, about which our knowledge has, 
within the last two or three years, been greatly extended, and 
which have proved to be of very special interest. 
Among these are two genera, called by their describer, Pro- 
fessor Cope, Synoplotherium and Mesonyx , each represented 
by a single species, S. lanius and M. obtusidens ; the latter the 
size of a large wolf, the former somewhat larger, both from the 
Eocene of Wyoming. These, like so many of the animals of 
the same period of the world’s history, present such a com- 
bination of characters, that it is impossible to place them in 
either of the existing families of the order to which they 
belong, being in some respects bear-like, in others dog-like, and 
in some being more generalised than are any existing members 
of the order. For instance, their claws had not that narrow, 
compressed, curved, and sharp-pointed form seen more or less 
in all modern carnivores, and in the highest degree in the most 
typical or specialised members of the group, the cats ; but they 
were nearly flat, straight, and blunt (from whence it has been 
conjectured that they were adapted for an aquatic life), and 
two bones of the carpus, the scaphoid and lunar, which in all 
existing carnivora (even including the seals) are united to form 
a single bone, were distinct from each other, as in the majority 
of mammalia. The lower canine teeth were placed very close 
to the fore part of the jaw, which appears to Professor Cope “ a 
special modification for peculiar habits, which,” he says, “I 
suspect to have been the devouring of the turtles, which so 
abounded on the land and in the waters of the same period. 
The slender symphysis could most readily be introduced into 
the shell, while the lateral pressure of the upper canines with 
the lower would be well adapted for breaking the bony cover- 
ing of those reptiles.” 
