EVOLUTION OF THE SKULL AND DENTITION OF OLIGOCENE TITANOTHERES 



463 



^ Allops serotinus ■"■ Brontops brachycephalus " Brontops robustus 



Figure 393. — Skulls of the menodontine and brontotheriine groups 



Palatal view. One-tweirth natural size ■ ^ , „ i 



Menodontine group: A, Brontops brachycephalus, brachycephalic, grinding teeth of moderate width. B, Bronlops robustus, skull very large 

 and brachycephalic, grinding teeth wide, incisors and canines massive. C, Allops serotinus, skull more elongate, grmding teeth of inter- 

 mediate proportions. D, Menodus giganteus, dolichocephalic, grinding teeth elongate, tooth rows rectilinear. 

 Brontotheriine group: E, Megacerops bucco, skull base very brachycephalic, grinding teeth broad, tooth rows curvilinear, fourth premolar sub- 

 molariform, canines small. F, Brontotlierium curtum, skull very large, skull base long but tooth rows curvilmear, grmdmg teeth wide, 

 fourth premolar submolariform. 



