1888. ] 75 [Cope. 
sufficiently open to display the crowns of the teeth. The rest of the skull 
is mostly wanting, though some parts of the base are probably preserved 
in the mass of matrix. 
The first incisor is directed nearly vertically downwards. The external 
face of the crown is an oblique, wide vertical oval, convex on the internal 
and obliquely truncate on the external edge. The crown of the second 
incisor is smaller and more acuminate ; there is no such difference in size 
between it and the first, as in Hyotherium waterhousei and other species of 
that genus, and both teeth are smaller than the corresponding ones in the 
Dicotyles torquatus. The superior canine is very robust. Its posterior edge 
is sharp, and the external face is flat, with a longitudinal shallow groove 
near the middle. The fourth premolar is wanting from both sides, but a 
space close behind the canine is probably its alveolus. A short interspace 
separates it from the third premolar. The latter has two roots and its 
base is nearly as long as that of the second premolar. The crown is lost. 
The second premolar is longer than wide, and is wider behind than before. 
It consists of an external cusp which has an angular apex of moderate 
elevation, and a basal internal cingulum. The latter arises posterior to 
the anterior base of the crown as a narrow ridge, and speedily expands 
posteriorly, enclosing a basin with the external cusp. It does not rise 
into a tubercle. The first premolar is as wide as long, aud has a subquad- 
rate base. It has but one, a simple external cusp, from the anterior part 
of which a transverse straight ridge extends inwards and ceases abruptly 
above the internal base. The posterior base of the tooth is therefore ex- 
panded, forming a table, while there is a rudimental anterior cingulum. 
No internal or external cingula. 
The first and second true molars are of subequal dimensions,and are 
larger than the first premolar. The base of the first is subquadrate and 
slightly oblique. Its four cusps are connected by wear, so that I cannot 
determine the presence of intermediate tubercles excepting one near the 
centre of the crown. A cingulum, except on the inner side ; the external 
faint. In the second true molar two intermediate tubercles are visible, 
but the anterior is fused with the external and internal anterior tubercles, 
so as to form a transverse crest, depressed in the middle. The posterior 
intermediate is in front of the posterior pair of tubercles, and there is no 
third or posterior cingular tubercle. Cingulum present except on inner 
side of crown, faint on external side. The third true molar is composed 
like the second, with the addition of a heel, and a tubercle on the inner 
side stopping the valley between the two cross-crests. The intermediate 
tubercles of this tooth are more conspicuous than in the m. ii, and the an- 
terior is of equal elevation with the interior and exterior of the first row. 
This row is now quite oblique, looking posteriorly inwards. The heel has 
a median tubercle about the size of the second intermediate, which is 
flanked on each side by a plicated border or outline. The enamel of all 
these teeth is smooth. 
There are three incisors in each ramus of the lower jaw. Their crowns 
