XI EXTINCT PECORINES 329 
Ancodus (or Hyopotamus, as it has been called) is also Oligo- 
cene in range, and its remains have been found in the same 
countries as have those of Anthracotheritum. Both genera are 
indeed closely allied. -Ancodus seems to be a more shghtly- 
built creature. The skull looks weaker, but presents much the 
same features of organisation. In A. velawnus, a species found in 
French rocks, a metacarpal of digit I. was present in the manus, 
while A. brachyrhynchus had a completely five-fingered manus. 
The Miocene genus Merycopotamus (from the lower layers of 
the Siwahk formation in India) is more distinctly selenodont 
than the forms already discussed. On this ground it has been 
placed in a separate sub-family. As, however, in other respects 
it does not depart from the Anthracotherian type of structure, this 
proceeding seems to be hardly necessary. There are two species 
known, of which one, JZ nanus, is, as its name denotes, a dwarf 
form. 
Fam. Cacnotheriidae.— While the last family consisted 
of animals rather more akin to the Pigs, the present is more 
Pecorine in its characters. The molars are selenodont; but as in 
the Tragulidae the premolars are more of the nature of cutting 
teeth. The dentition, like that of so many of these early 
Ungulates, is complete, and the canines are not prominent. The 
feet are four-toed, the lateral toes not reaching the ground. 
The principal genus is the Eocene and Miocene Caenothervum. 
Of this genus there were a considerable number of species all 
European in range, and of small size—not more than a foot or so 
in length. Their small size is suggestive of the Chevrotains. 
In the skull the orbital cavity is nearly or quite surrounded 
by bone, and the tympanic bulla is large and inflated. A 
common feature of Artiodactyles, a failure of the nasals and 
maxillae to meet at the side of the face, is to be seen in this 
ancient forerunner of the Pecora. 
Plesiomeryz, also European, and from the same geological 
horizon, is a very closely allied form. 
Fam. Xiphodontidae.— This family consists of slender, 
small Artiodactyles which are, like the Caenotheriidae, related 
to the Pecora. They are confined in their range to Europe. 
The type genus Yiphodon has selenodont molars and elon- 
gated, slender, cutting premolars. The dentition was complete 
and the canines not highly developed. Like Caenotherium, 
