Prof. Owen on Life and Species. 39 
and permanent. It exemplifies a condition intermediate to that 
in Paleotherium and Equus. It is not that the jaws of the 
Horse are too short to hold the fuil complement of grinders; on 
the contrary they are relatively longer than in the Paleothere, 
being specially produced between “the grinders and cutters : 
the first grinder might seem, indeed, to have been taken away in 
order to add to the space for the application of the ‘bit. The 
transitory and singularly small and simple denticle, fig. oe 
P.1, compared with the large contiguous massive molar 
in the Horse, exemplifies the rudiment of an ancestral erties 
ture, in the same degree as do the hoofless ‘ splint-bones,’ ib., 
Equus, u, tv :. just as the spurious hoofs dangling therefrom in 
tpparion, ib. Il, Iv, are retained rudiments of the function- 
ally ‘developed lateral hoofs in the broader foot of Paleothe- 
rium, ib. 11, 
Other cine links of this series of species have been sup- 
plied ; as, e. g., by the Paloplotherium* of the newer eocene 0 
Ho rdwell, Hants., ee “ae Paleotherium awrelinense from the 
‘molasse marine’ of O rleans,f and by the Paleotherium hip- 
poides of the oun ae calcareous beds of Sansan, all whic 
deposits are miocene, or are transitional between eocene and 
miocene. In the first-cited example, the swollen termination 
of the lobe of the molar, answering to c, m, fig. 268, remains 
longer as a detached column, m, fic. 269. In the two other 
Paleotherioids, the whole foot is longer and more slender, with 
a longer and thicker middle toe, than in the older eocene "type- 
genus, whence the generic name Anchitherium applied to them 
by von Meyer.t It is interesting, also, to find that the transi- 
tional character is further m arke d by the smaller relative size 
of the first premolar, hate Anchitherium intervenes, as in 
the modification of the feet, between the Paleotherium and 
Hipparion. 
Thus amply and satisfactorily has been fulfilled Cuvier’s 
requisition of 1821 :—‘Entre le paleotherium et les espéces 
@aujourd’hui l’on devrait decouvrir quelques formes intermé- 
diaries.’ How, then, is the origin of these intermediate grada- 
st 
Zebra, and Ass, the difficulty of interbreeding would be greats 
and the probability of fertility less, supposing those extinct 
— modification, as the = Sromeenagne eae ymard, began to be shown - 
the upper eocene at Velay, e. g., ere Paleo wa cropet bad peal eipag oe 
(Bulletie du Congrés Scientifique de France pete a heat 1855.) es 
Also in the ——— eocene of the Basin of the cm os 
Anchitherium oceurs, also, in the ‘ marins apace or lower miocene, ee 
Sesion aR : 
