MCEEITHEEIUM TEIGONODON. 129 



M. 8499. Posterior portion of right ramus o£ mandible with the molars. Type specimen described 

 in Geol. Mag. [5] vol. i. p. 112. Figured PI. IX. fig. 5. 



The characters of the teeth are as follows :■ — 



if . 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. 



M. 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 in. 2, and similarly 

 m. 2 is smaller in proportion to m. 3. 



M. 3 is quite unworn ; it differs considerably from m. 3 of M. 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 M. 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. 1 2-6 ? 



m.2 3-2 ? 



«?. 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 skuE. Vertebrae described above 

 (pp. 112-117), and some of them figured (text-figs. 44-47). This specimen may be 

 merely a large individual of M. lyonsi. Middle Eocene. 



