MCKIUTIIEEIUM. 
109 
end the superior border runs upwards and backwards at right angles to it, so 
that the very sliort coronoid process [cor.) does not rise above the articulation. The 
condyle itself [cond.) is elongated from within outwards and short from before 
backwards ; it is convex in both directions and is wider on the outer than on the 
inner side, which is supported on a flange or buttress of bone arising from the inner 
face of the ascending ramus. From tlie condyle the posterior border runs down- 
wards and backwards in a wide sweeping curve, forming the broadly rounded 
angular region which projects somewhat below the ventral border of the horizontal 
ramus. The outer face of the ascending ramus between the thickened anterior 
border and the buttress which bears the condyle is deeply concave, the bone being 
very thin. 
Lower Dentition . — There are two pairs of incisors (PI. X. figs. 1, 1 a, i. 1, i. 2). 
These teeth are procumbent and directed forwards, their upper surface forming a 
continuation of the spout-like upper face of the symphysial region of the mandible. 
The first incisors are much the smaller, and are closely crowded together between 
the second pair. They seem to have been prismatic teeth with very long crowns and 
roots ; their transverse width would be about 2'5 cm. The second incisors are a pair 
of large tusks, which seem to have been more or less triangular in section near the 
top of the crown, but ovate further down. No well-preserved examples have been 
found in situ in the jaw, but two specimens which may be regarded as these teeth 
are here noticed. One of them is a young tooth in which Avear has just commenced ; 
the upper face of its crown is concave from side to side, the inner face fiat, while the 
ventral face is convex and meets the upper face externally in an angle forming the 
sharp outer edge of the crown, which is chisel-shaped, but thicker internally than at 
its outer side. The wear-surface is nearly at right angles to the long axis of the 
tooth ; it is narrow, but as wear proceeded would increase in depth till towards the 
base of the crown it Avould be such as is found in the second older tooth referred to 
below. The crown is covered with enamel, of which the surface is finely sculptured 
with vermiculate markings below and irregular longitudinal ridges above. The 
enamel extends much further down the upper and lower faces of the crown than on 
the sides. In the older tooth the wear-surface is broad, flat, and oval in outline ; it 
is slightly inclined to the long axis of the tooth, and on the inner and outer sides 
has already passed below the level of the enamel-covered surface, so that the enamel 
forms two separate bands, one on the upper, the other on the lower face. The root 
is very long and slightly curved, Avith a longitudinal groove on the concave side. At 
this stage, at any rate, the root was closed. 
The third incisor, canine, and first premolar are Avanting in the mandible. 
The anterior premolar (PI. IX. figs. 3, 3 a, pm. 2) is comparatively small, and narroAV 
from side to side. It consists of a large main cusp, in front of Avhich there is a small 
tubercle Avhich may belong to the cingulum. Behind there is a large talon rising in 
