202 Bulletin Ajnerican Museum of Natural Histof-y. [Vol. XIX, 



with the Ohgocene, and of the Uinta with the Upper Eocene. 

 They are probably of approximately the same age as the 

 White River beds of Swift Current Creek, Canada, with which 

 they have three species in common, probably a fourth {'' PalcB- 

 olagus turgidus" from Swift Current Creek probably is P. 

 brachyodon), — a fair proportion out of so limited a fauna. 



Descriptions of Species. 

 MARSUPIALIA. 



Peratherium titanelix, spec. nov. 



Type, No. 9603, a lower law with p, and m^-^ and alveoli of the 

 remaining teeth except incisors. 



This species is about the size of P. hiintii of 

 the Oreodon Beds, and resembles it in the rather 

 y\UfT|WW;^L/ ( short premolar region, the premolars and canine 

 small, close together without any diastemata. 

 The molars are similar to those of typical Pera- 

 'i ^_B*s*&a_/j f/z^r/a from the Phosphorites, but the premolars 



are very distinct, crowded, and reduced antero- 

 posteriorly, the cusps recurved instead of sym- 

 ,.f's-,^ Fcratheriutn metrical as in Peratheria from the Phosphorites, 



titaneux. 1 ype speci- ^ ■ n ^ c 



men, twice natural size. and m P. jugax of Cope. The anterior part of 

 of't°eeth';' ^ '' '""" ^'^"^ the jaw is rather short and deep and the canine 

 directed more upward than in P. fugax. 



Measiireutents. 



Length pi_ m4 7.3 mm. 



Length m^-^ 4.2 



Depth jaw under xn^ 1 .g 



INSECTIVORA. 



Apternodus mediaevus, gen. et spec. nov. 



Type, No. 9601, posterior half of a lower jaw with two complete 

 molars and the root of another. 



Molars composed of high trigonid and mmute basal talonid. Proto- 

 conid high, sharp, and triangular, paraconid and metaconid subordi- 

 nate. Dentition probably i? Ci p3 m3 . 



Talonid a small sharp cusp on mj ; on m, it is a minute postero- 

 internal basal cusplet. The third molar a little smaller than the 

 second; both are two-rooted, the anterior root wider transverselv. 



