171 — 30 INDIAN TERTIARY AND POST-TERTIARY YERTEBRATA. 
Family 3. — 0RE0D0NTID2E. 
Characters . — This family, taken here as comprehending the genera Oreodon, 
Eporeodon, Agriochcerus and Merycochoerus , is distinguished from the last by the mandible 
lacking the characteristic descending plate at the ‘ angle,’ and by the nearer approach 
in the plan of structure of the molars to the true ruminants. The family has 
hitherto been recorded only from the tertiaries of north America, but the molar 
tooth described below would seem to indicate that it formerly existed in north- 
western India. It will be remembered that in the previous volume of this work, 1 it 
was pointed out that the lower molars of the extinct Siwalik camel present a 
remarkable affinity to those of the American cameloid Auchenia , and since the 
oreodons are considered to be intimately connected with the tertiary ancestors 
( Procamelus , etc.,) of the modern camels, it is a fact of much interest to find that the 
Siwalik camel lived in a country which had also a representative of the oreodons 
and agriochseres. 
Genus AGRIOCHCERUS, 2 Leidy. 
As the reference of the molar described below to this genus is merely provisional, 
the generic characters are not given. The genus is stated to have relationship with 
Hyopotamus. 
Species, non. det. 
Upper molar . — The specimen provisionally referred to the above genus is an, 
unfortunately incomplete, upper molar ; it is represented from the masticating surface 
in figure 2, of plate XXIII, and will be seen to belong to the left side of the 
cranium. This tooth has been scarcely affected by wear, but has lost a part of its 
postero-internal column, as' well as the external walls of both the outer columns. 
It was collected in 1878, by Mr. F. Fedden, in the lower Manchhars of the L&ki 
TIills of Sind. 
The crown carries only four columns without the slightest trace of the fifth 
accessory column. The inner columns are stout and low; rounded and conical on 
their inner, and regularly crescentic on their outer sides : they are more symmetrical 
than those of any of the previously described genera. The median longitudinal 
valley is deeper and more distinct than in the preceding genera, whereby the outer 
columns are more widely separated from the inner, and are not thrust within their 
crescents. The two outer columns are closely approximated at their bases, so that 
there could not have been a wide transverse valley terminating externally in a 
projecting loop. The external surfaces of the outer columns were probably nearly 
vertical, and not produced at their angles, as in the preceding genera. There is a 
1 p. 61. 2 From, agrios, wild, and choiros, a pig. This genus is generally, as here, classed with the Oreodonlidce 
(see Nicholson’s “Palaeontology,” 2nd ed., p. 352), hut Professor Leidy is inclined to refer it to a distinct family, (see 
“ Contributions to Extinct Vertebrate Fauna of Western Territories,” p. 216.) 
