ipoi.] Matthew, Additional Observations on the Creodonta. 33 



^ 



m.l 



m.2 



lower jaw has dropped out early, its alveolus being closed up. 

 Median (? upper) incisors with large very much compressed root 

 and small crown. Lateral incisor 

 with large root of oval section and 

 small pointed crown. Canine large 

 of round-oval section. 



Lower Teeth. — Canines large, 

 moderately stout, regularly oval in 

 section, set near together (inter- 

 space about half width of canine). 

 First premolar one-rooted, second 

 two-rooted, third true premolar 

 emerging from the jaw, stout, with 

 protoconid directed strongly back- 

 ward, wide, square-based, low tren- 

 chant heel and no anterior basal cusp. No indication of a fourth 

 permanent premolar could be found in the immature individual, 

 but the state of preservation of the specimen does not make it 

 possible to disprove the existence of one. The temporary pre- 

 molar is indicated by some remains of an alveolus. In the adult 



ml 



Fig. 13. Pachycpna gigantea Osborn 

 & Wortman. Three upper molars in 

 place. Crown view, one-half natural size. 

 Young individual. No. 2950, Wasatch 

 Beds, Big Horn Basin, Wyoming. Amer. 

 Mus. Exped. 1896. 



Fig 14. Pachycena gigantca^ No. 2959. Fragmentary lower jaw, external view, one-half natural size. 



jaw, as already observed, the temporary fourth premolar had fallen 

 out and its alveolus closed without replacement. The first and 

 second molars have a vestigial metaconid ; traces of it are dis- 

 cernible also on the third. All three are shaped like those of P. 

 \yanuary, igoi.\ <i' 



