26 AGRIOCHOERUS. 
of the two sides; its median suture being about five lines above the alveolar 
margin. (Fig. 6.) 
Inferior Maxilla—The two fragments of lower jaw, preserved in connection 
with the specimen just described, and comprising as much of the body of each side 
as contains the hinder five molars, present pretty much the same form as the cor- 
responding portion of the jaw of the Camel, but are relatively deeper and less 
convex externally. (Fig. 5.) 
The alveoli have a remarkable degree of descent forward in relation to the base 
of the jaw; the depth of the bone below the posterior lobe of the last molar being 
twenty-one lines, whilst it is only eleven lines below the last premolar. 
Internally the lower jaw is much more convex than externally, especially in 
advance of the first true molar, and also posterior to this upon the alveolar portion 
of the bone. 
Just above the thick, rounded base of the jaw internally, and below the position of 
the first true molar, a concavity commences, which gradually expands and deepens 
to a line with the posterior lobe of the last molar, when it abruptly increases and 
then continues to the broken margin of the specimen, so that it is probable the 
technical angle of the jaw within is deeply concave, as in the Tapir. 
A little more than half way below the position of the last premolar externally 
is a small foramen directed backward, which is probably an offset from the inferior 
dental canal. 
Dentition—The molar teeth of Agriochoerus are certainly ruminant in their 
type, and the true molars in both jaws are constructed upon the same pattern as 
those of all recent ruminants, each being composed of two symmetrical pairs of 
demiconoidal lobes, with an additional odd lobe to the last lower molar. In the 
specimen above described, the posterior six molars are preserved in the upper jaw, 
and the posterior five in the lower jaw. 
The molars in both jaws successively decrease in size from behind forward. 
Those above, on the two sides, are nearly parallel internally, and from thirteen to 
fourteen lines apart, but externally their line is convergent forward. 
Superior Molars.—(Figs. 5, 6-10.) The upper true molars resemble very closely 
the corresponding teeth of Hyopotamus deprived of their anterior median or ac- 
cessory lobe. As in this genus, their transverse diameter is greater than that 
antero-posteriorly; the result apparently of the expansion of the teeth from the 
condition in which they exist in the recent ruminants generally. The lobes are 
low and spread wide apart, and the interlobular spaces are broad and shallow; 
thus the perpendicular height of the outer lobes of the last molar is four lines, 
and the distance between the summits of the anterior pair of lobes is three lines. 
The outer lobes conjoin externally to form a prominent median convexity, and 
another, similar but not quite so large, is formed by the union of the anterior angle 
of the antero-external lobe with the contiguous prolonged arm of the summit of the 
antero-internal lobe. The surface of the outer lobes, between the external con- 
vexities, is transversely concave with the feeblest degree of median elevation, and 
inclines very much inward. Internally the outer lobes are convex and nearly 
vertical. 
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