226 EOCENE FAUN^. 



distinguished from the other members of the genus by the great projection 

 of the heel of the hist molar and its constricted forjn. The fourth premo- 

 lar is also larger than in the other species, and has a large anterior basal 

 tubercle, which is much better developed than in the other species. 



In the true molars the three anterior tubercles are well distinguished, 

 and the anterior, though the smallest, is well on the inner side. The pos- 

 terior inner cusp is a little larger than the anterior outer. In the first and 

 second true molars the inner margin of the heel is elevated, inclosing a 

 basin-like fossa, and rises into a flat cusp posteriorly. There is a small 

 median posterior marginal tubercle, which runs into a posterior cingulum, 

 and is wanting from the DeUafherium fundaminis. The tubercular has the 

 three anterior cusps distinct as in Didymictis sp., while the heel is longer 

 than in the known species of that genus. Its external border rises into a 

 prominent cusp with triangular base. The fourth premolar has a small 

 heel on the inner posterior side, and an acute anterior basal cusp. The 

 priiiciiial cusp is robust and the basal portion is widely grooved posteriorly 

 (apex lost). True molars with an external cingulum. Enamel obsoletely 

 wrinkled. Length of true molar series, .024; of fourth premolar, .0075; 

 length of last molar, .008; width of heel of second true molar, .005; length 

 of crown of do., .007. 



A second specimen of this species includes a mandibular ramus which 

 supported the last five molars, and a maxillary which supjiorted the last four 

 molars, both evidently jjarts of the same animal. Tiie third inferior pre- 

 molar, which is wanting in the type specimen, is present here. It consists 

 of an elevated acute simple cusp, which has median anterior and posterior 

 ridges, and a low internal ridge, which separates a lateral plane from a pos- 

 tero-intenial plane. There is a rudimental anterior basal lobe and a short 

 heel with transverse jjosterior edge. No lateral cingula. 



A third specimen consists of parts of the maxillary bones of one indi- 

 vidual, which support the last four sujjerior molars in better preservation than 

 those of the specimen described above, where two of the four are l)roken. 

 The two individuals clearly represent one species. The fourth premolar is 

 transverse, and consists of a principal large external cusp and a smaller 



