30 

 Poebrotheridm wiLSONr, Leidy. 



Plate VIII, figs. 8 and 9. 



This species, made known by Leidy in 1847 (Proc. Acad. Nat. Sci. Phila., vol. Ill, p. 322), 

 from the greater part of a skull from the Oligocene (White River) of Nebraska, is represented 

 in the 1904 collection from the Cypress Hills beds by two separate lower last temporary molars, 

 one of which remains in a portion of the jaw. These teeth are composed of three double 

 lobes decreasing in size to the front. The jaw fragment in which the molar is preserved, has 

 a depth agreeing with that of the lower jaw of the type skull, fully described and figured by 

 Dr. Leidy in 1854* in his classic " Ancient Fauna of Nebraska" (Smith. Contr. to Knowledge, 

 vol. VI). In advance of the molar in this specimen are the alveoli for the tooth next in front. 



Measurements. 



MM. 

 Lower right last temporary molar : — 



Antero-posterior diameter 1 2 • 3 



Posterior transverse " 7 ■ 



Anterior " " 4 • 5 



Lower left last temporary molar in jaw fragment : — 



(Plate VIII, figs. 8 and 9.) 



Antero-posterior diameter 100 



Posterior transverse " 6 



Anterior " " 4 



Depth of ramus beneath molar 130 



Leptemeryx esulcatus, Cope. 



No teeth from Bone coulee belonging to the 1904 collection can with certainty be referred 

 to this species, which is based on a worn upper, right molar of which the posterior half of the 

 ectoloph is broken away. In size the type of L. esulcatus is between one-third and one-fourth 

 smaller than the molars of L. eravsi, Leidy. The lower teeth figured by Matthew in his paper on 

 the fauna of the Titanotherium beds, 1903, p 223, fig. 15, and referred provisionally to L. 

 esulcatus, belong evidently to a species considerably larger than the one represented by the 

 type of L. esulcatus. 



Leptomeryx mammifer, Cope. 



t Leptomeryx mammifer, Cope, 1885. The White River beds of Swift-current river, North - 

 "West Territory, American Naturalist, vol. XIX, p. 163 ; name only. 



Leptomeryx mammifer, Cope, 1885. Geol. and Nat. Hist., Survey of Canada, vol. I, new 

 series, part C, appendix I, p. 84. 



Leptomeryx mammifer, Cope, 1889. The Vertebrata of the Swift-current river, II, American 

 Naturalist, vol. XXIII. p. 154. 



Leptomeryx mammifer, Cope, 1891. The species from the Oligocene or Lower Miocene beds 

 of the Cypress hills ; Geol. Survey of Canada, Contr. to Can. Palaeont., vol. Ill, (quarto), 

 pt. I, p. 22, pi. XIV, figs. 6, 6o, 7, la. 



Leptomeryx mammifer, Matthew, 1899. A provisional classification of the Fresh-water 

 Tertiary of the west, Bulletin Amer. Mus. Nat. Hist., vol. XII, article HI, p. 61. 



* For tliis species see also. 1869. The Extinct Mammalian Fauna of Dakota and Nebraska ; Jour. Acad. Nat. Sci. Phila., 

 second series, vol. VII, p. 141, pi. XIII. 



