14 
EDWAED B. POULTON. 
far too early a stage for any attempt at such description. 
Successive vertical, transverse sections through the first or 
anterior upper teeth, beginning anteriorly, are shown in 
PI. II a, figs. 1 — 3. In the lower jaw, I have already stated 
that I cannot be certain of the presence of this tooth. The 
sections indicate a long, narrow, very completely calcified 
tooth, directed downwards and somewhat inwards, the apex 
being very nearly in contact with the lower surface of the oral 
epithelium. There is one chief cusp, and apparently a second 
smaller one, externally placed (shown at PI. II a, fig. 3, o. c.) ; 
but I cannot feel very sure about the latter, for the sections of 
this tooth were not so satisfactory as those of the others. It 
is quite clear that the tooth is far smaller than the second and 
third, which lie behind it. These latter are shown for both 
sides of the upper jaw in figures of a series of vertical trans- 
verse sections (PI. II, b and c, figs. 4 — 15), and those of the 
right lower maxilla are seen in a figure (see fig. 16) of a dis- 
sected preparation, b being the anterior and c the posterior of 
the two teeth, seen from within and above. The comparison 
of b and c in the sections and in fig. 16, at once shows that 
the anterior or second tooth is a larger tooth than the third * 
It is also obvious from the figures that each of the second teeth 
possesses two large calcified cusps (coloured red in the figures), 
which are placed respectively on the anterior and posterior end of 
the inner side of the upper teeth, and of the outer side of the 
lower teeth, and which are therefore adapted for interlocking 
in mastication. The rest of the tooth is uncalcified. The 
surface (shown in b, fig. 16) is smooth and mammillated, shal- 
low furrows separating the low rounded elevations and ridges. 
The sections (b, figs. 6 — 11, o. c.) indicate that there are many 
(probably four or five) small, uncalcified outer cusps in the 
upper teeth, while the corresponding inner part of the lower 
tooth (shown in fig. 16) has been accidentally cut away; but 
there is no doubt that its appearance is, in this respect, very 
similar to that of the third tooth (fig. 16 c), viz. that its border 
is crenulated from the presence of small, soft inner cusps, of 
which only the anterior now remains. 
