^KERlTJrEElUM TRIGONODON. 
129 
M. 8499. Posteriof portion ot‘ rioht minus of mandible with the molars. Type specimen describeil 
in Geol. Mag. [5] vol. i. p. 112. Figured PI. IX. fig. .5. 
The characters of the teeth are as follows : — 
M. 1 is a bilophodont tooth with a small posterior lobe ; each transverse crest 
consists of two tubercles. Most of the outer half of the tooth is wanting ; the inner 
half consists of a high anterior cusp and a somewhat lower posterior one, separated by 
a deep valley. 
]\[. 2 also wants a great part of its inner half. It is similar to m. 1 except that there 
is a posterior lobe consisting of a large blunt tubercle, which lies immediately behind 
the outer tubercle of the posterior crest. These two teeth are much like the 
corresponding ones of M. lyonsi ; but m. 1 is smaller in proportion to m. 2, and similarly 
m. 2 is smaller in proportion to m. 3. 
M. 3 is quite unworn ; it differs considerably from ??i. 3 of AI. lyonsi. Like the 
other molars, it consists of two transverse ridges with a talon. The transverse ridges 
are placed somewhat obliquely ; the anterior one consists of a' high pointed outer 
tubercle and an inner one which is partially divided into two. In the posterior crest 
the outer half again consists of a high pointed tubercle, but the inner half here consists 
of two subequal tubercles. The talon is composed of a large tubercle lying in the 
same line as the outer tubercles of the crests, and on its inner side there are several 
small tubercles ; on its outer side the cingulum is well developed. The talon as a 
whole is triangular in outline, its posterior angle being on the outer side of the tooth. 
In AI. lyonsi (PI. IX. fig. 2 ; PI. X. fig. 1), on the other hand, the talon is much wider 
and consists of an outer and inner tubercle which form a broad crest, thus converting 
the tooth into a trilophodont one. This difference in the talons appears to justify the 
separation of the present form as a distinct species at least, and not improbably further 
material will show that a new genus must be established. The enamel of the whole 
tooth is raised into irregular ridges and small tuberosities. The dimensions (in 
centimetres) of the teeth are : — 
Length. Width. 
m. \ 2' 6 ? 
m. 2 3-2 ? 
w. 3 4 2'4 
The length of the molar series is 9’8 cm. 
Moeritherium sp. 
C. 10005. Nearly complete vertebral column with very imperfect skull. Vertebrse described above 
(pp. 112-117), and some of them figured (text-figs. 44-47). This specimen may be 
merely a large individual of AI. lyonsi. Middle Eocene. 
S 
