OF THE MESOZOIC MAMMALIA. 
209 
Enough of the palate is preserved to show that the inner surface of the teeth is 
the one exposed. The fragments of bone in front of canine cannot be recognized as 
incisors. The canine is proportionally large, directed backwards and recurved, with 
a faint median groove, which may indicate a double fang. Behind this is a small, 
columnar premolar; a space which may have been occupied by or may represent 
a diastema, follows; the premolar behind this is extremely small and functionless, 
and from this we might infer thatjim^ was permanently missing; is slightly larger 
and bifanged, (Mes. Mamm., p. 49); pm, maybe distinguished from the molars by the 
absence of a cingulum, but it is most interesting to observe that it is apparently in 
course of transformation into the molar pattern, the two fangs are not set in the line 
of the ramus, but obliquely, and the long diameter of the crown is also slightly 
rotated into a transverse position, with its apex internal. The seven molars are nearly 
uniform in size and very similar in pattern. They slightly increase in size from the 
first to the fourth and fifth, and then diminish ; there is a corresponding downward 
curvature of the wearing surfaces. The inner line of the crowns is concave, and the 
outer, convex; this curvature is shown to be 
natural, and not the result of pressure, by the 
wedge-shaped sections of the crowns (fig. 4) the 
inner faces being much narrower than the outer, 
and the proximal surfaces closely applied to each 
other. The crown is supported upon two power- 
ful fangs, placed transversely to the jaw; the 
convex inner slope is marked by a faint cingu- 
lum and rises to a narrow point, so that the 
direct internal view resembles that of the Stylo- 
don molar ; judging from the contour of the wearing surface, the outer slope is 
divided by a vertical groove, g; the summit of the crown slants obliquely out- 
wards from the internal tip, but the tooth is so obliquely placed in the maxilla 
that the wearing surface is not far from the horizontal plane; this surface is 
concave from side to side, and, under a close examination, reveals a complex 
pattern: two enamel ridges, e, diverge from the inner apex of the wedge, along 
the sides of the crown, becoming thinner and less prominent towards the outer 
surface ; from the inner angle of the thus formed, a median ridge, e\ traverses the 
crown, which is also less prominent as it extends outwards, dividing the surface into 
two valleys opening outwards. The crown is thus divided into transverse ridges and 
grooves like that of a rodent, but the resemblance is not complete since the median 
ridge is not the result of an infolding of the side of the crown, but is apparently the 
remnant of a folding of the enamel on the wearing surface, which will disappear in 
course of further attrition, A partly worn Phascolomys molar presents a somewhat 
similar appearance, (fig. 15, B e, e^). This description of the molar pattern differs widely 
Figure 4. The inner surface of the left 
maxilla of Kurtodon pusillus, enlarged 5i di- 
ameters. 
