The foot of _Hipparion_, however, as has been
previously mentioned, differed from that of the Horse in the
fact that whilst both possess the middle toe greatly developed
and enclosed in a broad hoof, the former, in addition, possessed
two lateral toes, which were sufficiently developed to carry
hoofs, but were so far rudimentary that they hung idly by the
side of the central toe without touching the ground (see fig.
230). In the Horse, on the other hand, these lateral toes, though
present, are not only functionally useless, but are concealed
beneath the skin. Remains of the _Hipparion_ have been found
in various regions in Europe and in India; and from the immense
quantities of their bones found in certain localities, it may
be safely inferred that these Middle Tertiary ancestors of the
Horses lived, like their modern representatives, in great herds,
and in open grassy plains or prairies.
Amongst the Even-toed or _Artiodactyle_ Ungulates, we for the
first time meet with examples of the _Hippopotamus_, with its
four-toed feet, its massive body, and huge tusk-like lower canine
teeth. The Miocene deposits of Europe have not hitherto yielded
any remains of _Hippopotamus_; but several species have been
detected in the Upper Miocene of the Siwalik Hills by Dr Falconer
and Sir Proby Cautley. These ancient Indian forms, however, differ
from the existing _Hippopotamus amphibius_ of Africa in the fact
that they possessed six incisor teeth in each jaw (fig.
Pages:
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472