NIMEAVID^. 995 



truncate anteriorly. The frontoparietal suture crosses the apex of the 

 frontal space. 



Foramina. — The infraorbital foramen is large and subtriangular. Its 

 posterior border is directly above the middle of the anterior root of the 

 superior sectorial. The lachrymal is small. There are two nasoorbitals 

 perforating the orbital plate of the palatine, of which the superior is the 

 larger. The incisive foramina are large, and the palatals are small and 

 opposite the anterior border of the (first) third premolar. The postparietal 

 is well below the sagittal crest. The postglenoid is small. The dental 

 foramen is large, and its center is below the middle line of the ramus, and 

 below the anterior border of the base of the coronoid process. There are 

 three external mental foramina on both rami; one below the front of the 

 fourth premolar, one anterior to the front of the third premolar, and a larger 

 one below the middle of the surface to which the superior canine tooth is 

 applied. There are two anterior mental foramina which mark about the 

 thirds of the depth of the chin. 



Dentition. — The width of the premaxillary region gives space for a full 

 development of the incisors, which have robust bases. The canines, like 

 the incisors, are broken off. Their bases show them to have been of large 

 size, and of more compressed form than those of any of the species already 

 described; Their long diameter considerably exceeds the length of the 

 diastema which separates them from the third (first) premolar. There is no 

 indication of the existence of a second premolar. As the outlines of the 

 maxillary bones diverge strongly, the base of the third premolar is oblique. 

 Its crown is broken off, but it was evidently not as large a tooth as in the 

 species of Nifnravidce above described. Its base is one-half the length of that 

 of the sectorial. The sectorial has its pi'incipal cusp prominent and acute, 

 while its heel is low, but compressed and sharp. There is a rudiment of an 

 anterior basal lobe, as is figured by Leidy in the H. primoevus. This tooth 

 is characterized also by the very small size of its internal heel, which is 

 continued downwards as a perfectly straight ridge, without interruption, to 

 near the apex of the principal cusp. The edges of the tooth are little worn, 

 and they show at several ^^oints anterior and posterior to the principal cusp 

 a beautiful denticulate structure. The tubercular molar is large, but not 



