XXX INTRODUCTION. 
between the course of the extirpation of the Pliocene 
Mammals, and that which history shows to have reduced 
the numbers of the wild animals of continents and islands 
in connection with the progress of man’s dominion. The 
largest, the most ferocious, and the least useful of the 
pliocene species have perished; but the Horse, the Ass, 
the Hog, probably the smaller Wild Ox, the Goat, the 
Red-deer, and Roe, and many of the diminutive quadru- 
peds, remain. The present negative evidence supports the 
belief that the Human species had not been called into 
existence when the Mammoth, the tichorhine and lepto- 
thine Rhinoceroses, and the great northern Hippopotamus 
became extinct. Cuvier drew the same conclusion as 
to the Quadrumanous Order from the same grounds ; 
but the recent discovery of a true fossil portion of a Mon- 
key’s skeleton, (figs. 1, 2, and 3, p. xlvi,) im the same la- 
custrine deposits which abound in the remains of extinct 
Pachyderms, with similar discoveries noticed in the first 
section of the present Work, should teach caution in the 
application of conclusions from merely negative facts. It 
is probable that the Horse and Ass are descendants of a 
species of pliocene antiquity in Europe. There is no ana- 
tomical character by which the present Wild Boar can 
be distinguished specifically from that which was con- 
temporary with the Mammoth. All the species of Euro- 
pean pliocene Lovide came down to the Historical period, 
and the Aurochs and Musk-Ox still exist; but the one 
owes its preservation to special Imperial protection, and 
the other has been driven, like the Reim-deer, to high 
northern latitudes.* There is evidence that the great Bos 
* The observations of Mr. Murchison, in his great work on the Geology of 
Russia, 4to., 1845, pp. 471, 492 to 507, bearing upon the question of the specific 
identity of the existing with the fossil Aurochs, are highly interesting, and sup- 
port the conclusions to which I had arrived from anatomical comparisons. 
