22 

 HYPERTRAGTJLUS, Cope. 



Bulletin U. S. Geol. Survey Terrs., I., 1874, p. 26; Annual Report do., 1873 (1874), p. 502; American 

 Naturalist, 1889, p. Ill, pi. vi. 



Hypertragoltjs transversus, Cope. 



American Naturalist, 1889, p. 154. 



Indicated by two superior molar teeth of old individuals. They are of nearly twice 

 the linear dimensions of the only known species, H. calcaralus, Cope. The external cusps 

 are subconical, and the external rib which separates them in the Leptomeryx is wanting 

 here. Anterior cingular cusp small. The anterior horn of the posterior internal crescent 

 enters the notch between the external cusps, but does not fuse with either of them. 

 Slight cingula on the anterior and posterior sides of the internal lobes, which do not pass 

 round their internal sides. No external cingulum. Diameters : anteroposterior, 12 mm. ; 

 transverse (at base), 15 mm. Crown very brachyodont. 



LEPTOMERYX, Leidy. 



Proceeds. Academy Philada, 1853, p. 394; 1857, p. 89; Extinct Mammalia Dakota and Nebraska, 1869, p. 

 165 ; Cope, Proceeds. Amer. Philos. Soc, 1884, p. 23 ; ibid, 18S7, p. 3S9. 



Leptomeryx escjlcatus, Cope. 



American Naturalist, 1889, p. 154. 



A single superior molar indicates this species, which is of about the dimensions of 

 the L. evansii. It differs distinctly from this Tragulid in the greater convexity of the 

 external face of the external cusps, and the absence of the sulci which define an external 

 rib of that surface in the L. evansii. The rib which defines the external faces of the cusps 

 from each other is present. Anterior external cingular cusp small, continuous with 

 anterior cingulum. No internal nor external cingulum. Diameters of crown : Antero- 

 posterior, 6.5 mm. ; transverse, *1.5 mm. 



Leptomeryx mammifer, Cope. 



Report G. & N. H. Survey, Canada, 1885, App. C. p. S4 ; American Naturalist, 1889, p. 154. 



This species is represented by a fragment of the mandible which supports the last 

 two molars. Four superior molars add to the characters already derived from mandibular 

 teeth, but their reference to the same species is provisional, as they were found sepa- 

 rately. A tarsal cannon bone in the collection may belong to the same species. It is not 

 certain that it belongs to a Leptomeryx, but I leave it there until further information ena- 

 bles me to make a final determination. 



The crowns of the inferior molars are not prismatic, nor are they brachyodont. The 

 crown is well distinguished, and expands but little. The sections of the internal columns 

 are lenticular, while the external are crescentic. There are no basal columns or cingula 

 between the latter. In the second true molar, the horns ot the anterior internal crescent 

 join the anterior external crescent early on wearing, while the junction comes later in the 

 case of the two posterior columns. In the third true molar the anterior horn of the pos- 

 terior crescent does not reach the posterior external column, but only touches the anterior 

 internal column. In the same way, the posterior horn does not reach the external 



