79 



MAMMALIA. 



MULTIT UBERCULATA. 



PLAaiAULACID^. 



Ptilodus, Cope. 



Ptilodus prim^vus. Sp. nov. 



Plate XV, figs. 13 and 14. 



The specimen on which this species is based consists of an imperfect right mandi- 

 bular ramus in which the fourth premolar and the first molar are preserved. The fracture 

 in front exposes the large anterior root of the premolar and the small posterior root is seen 

 from the outer side. The lower front border of the crown of the premolar is slightly 

 excavated apparently for the accommodation of the posterior edge of a very small, closely 

 fitting third premolar. The socket for the base of the root of the incisor is seen on the 

 inner side and indicates a tooth of comparatively robust proportions. Behind the first 

 molar, the socket of the second molar is preserved, which, judging from its size, held a 

 tooth considerably smaller than the first molar. 



The characters of the teeth are as follows : — Fourth premolar with eleven serrations 

 on its edge ; on its inner side, five complete grooves preceded by three half grooves ; on 

 its outer side, five complete grooves preceded by one half groove. First molar with four 

 tubercles on its inner side and six tubercles on the outer side. 



Ptilodus primcevus is especially interesting on account of the small number of grooves 

 on the large cutting fourth premolar (approching ttie genus Meniscoessus in this respect) 

 and the slightly backward curve of the tubercles on the outer side of the first molar, 

 also suggestive of Meniscoessus. 



In the figures of the type of the species, the teeth are shown as they appear in the 

 specimen, but the first molar is evidently somewhat out of its true position of close 

 proximity to the fourth premolar. 



Belly River series. Red Deer river, 1901. 



BoREODON. Gren. nov. 



BOREODON MATUTINUS. Sp. UOV. 



Plate XV., fig. 15. 



This early type of mammal is represented by a single tooth, a premolar, having two, 

 slightly divergent roots. The crown is in the form of a laterally compressed cone, some- 

 what rounded above, angular in front, evenly rounded behind, with a well defined, 

 undulating cingulum encircling its base. A slight lateral concavity, more clearly 

 defined within, occurs in each side of the tooth near the base of the crown in line with 



