176 
PROFESSOR FLOWER ON A NEWLY DISCOVERED 
the inner surface into a thick crescentic ridge, slightly notched on the free projecting 
border. The form of the crown of the first tooth (i 1) cannot be accurately described, 
as it is altogether lost in the left side, and its anterior * half has been broken off on the 
right. In the second tooth (i 2) the outer surface of the crown presents an irregular 
shape, as it consists of a vertical median convex ridge and a pair of lateral lamellar 
expansions of unequal extent, the posterior border of the tooth being much shorter 
than the anterior. The distal free margin of the tooth is compressed and the apex 
rounded. The base of the crown is nearly as thick from without inwards as from side 
to side. The inner surface is hollowed near the cutting-margin, and has a considerable 
rounded tubercle at the base, so that the crown of the tooth may be described as con- 
sisting of an outer, trenchant, or principal ( a e c), and an inner, blunt, or accessory cusp 
( aic ), separated by a groove. 
The third incisor (?‘ 3) resembles the second in form, but the lateral lamellar expan- 
sions of the crown are. somewhat more developed. 
The canine tooth (c) only differs from the posterior incisor in being somewhat larger, 
and in trifling details of configuration. The apex is rather more pointed and conical, 
being supported by a median vertical ridge, not only on the outer, but also on the concave 
inner surface of the crown : the inner tubercle is relatively smaller to the principal cusp ; 
the cingulum is much notched ; the postero-internal margin of the crown is flattened, as 
if by the pressure of the succeeding tooth, a character also seen, though to a less degree, 
in the incisors. 
The first premolar (p 1) has only one root on the outer side of the tooth, and appa- 
rently a second one on the inner side. It is displaced somewhat within the line of the 
teeth before and behind it. The crown is shorter, broader, and less pointed than that 
of the canine, but its inner cusp or lobe is considerably more developed. 
The second premolar (p 2) assumes more the form of a true molar. It has two outer 
roots (anterior and posterior), and apparently a distinct root on the inner side. The 
external wall of the crown is oblong, nearly twice as high as it is broad from before 
backward, with a strongly marked crescentic cingulum, delicately ridged and tubercu- 
lated. Though the surface is in a general sense rounded or convex from before back- 
wards, indications are seen upon it of two vertical ridges, with a concavity between 
them ; the anterior ridge is the most conspicuous, and evidently corresponds with the 
single ridge developed in the preceding teeth. As in the incisors, canine, and first pre- 
molar, there is an inner lobe, but it is developed to a greater degree, and its sloping 
free surface shows two strong ridges or columns, which converge as they approach the 
grinding-surface of the tooth. These columns are separated from each other by a 
triangular depression, the base of which is crossed by the cingulum. The anterior and 
posterior surfaces of the crown are flattened, and the cingulum is continued all round 
* To avoid confusion, in describing the incisors I apply the terms anterior and posterior to the parts corre- 
sponding to those occupying these positions in the molar series. l( Outer” and “ inner” always mean the labial 
and the lingual surfaces of the teeth respectively. 
