Cope.] 500 [Jan 5( 



middle of the ramus. Inferior masseteric ridge much less pronounced. 

 The inferior part of the ramus is rohust below the base of the coronoid 

 process, but there is no indication of recurvature of the. edge. Mental 

 foramina two ; one below the front of the first true molar, and one below 

 the second premolar. 



The oval base of the canine is not flattened on either side; that of the 

 second tooth is flattened on the inner side. There is a great difference be- 

 tween the sizes of the last three premolars. The fourth is twice as large 

 as the third, and the second, judging from the space and the size of its al- 

 veolus, was much smaller than the third, and the crown was probably a 

 simple 'acute cone. The crown of the third is of that form, with the addi- 

 tion of a short heel. The long axis of the base of the crown is diagonal to 

 that of the jaw. The fourth premolar has a relatively larger heel than the 

 third, but it is shorter than the diameter of the base of the cusp. Its pos- 

 terior edge is elevated. The cusps ot the anterior pair of the true molars 

 are elevated, but the interior is the most so. The supplementary one is 

 not exactly in the line of the interior border of the crown. Each of the 

 inner cusps are connected with the base of the external by a ridge, which 

 together form a V. The posterior base is nearly surrounded by a raised 

 edge, which rises into cusps at the posterior lateral angles. Of these the 

 internal is the more prominent. The edge connecting these cusps is slightly 

 convex backwards, and evidently bears a part in mastication. The lateral 

 borders of the last molar are somewhat expanded, and the fifth lobe is very 

 short. No cingula on any of the teeth. 



Measurements. M. 



Length of dental series from " canine" exclusive 0265 



" true molar series 0140 



( longtitudinal 0040 



Diameters -canine" j transverse <0030 



Long diameter of base of "P-in. i" 0028 



. " "■ " P. m-ii 0017 



-r.. , -o • f vertical 0055 



Diameters P-m. iv 1 



t- anteroposterior 0050 



DiametersM. ii (transverse 0038 



(. anteroposterior 0050 



Length of crown of M. hi - .006f> 



Depth of ramus at P-m. iii 0090 



M. hi 0100 



MlXODECTES CRASSIUSCULTJS, sp. nOV. 



This mammal is represented by fragments of two mandibles from differ- 

 ent individuals ; one less and the other more worn by mastication. The 

 species differs from the last in its greater size, and in the relatively greater 

 length of the last inferior molar. The length of the posterior four molars 

 of the M. pungens equals that of the three true molars of the H. crassius- 



