GEOLOGICAL SURVEY OF THE TERRITORIES. 593 



LIMNOHYUS, Leidy. 



Proceedings Academy Natur.il Sciences, Philadelphia, 1872, p. 2i2, Palccosyops, Marsh, 

 Amer. Journ. Sci. Arts, 1872, p. 122, uot of Leidy, 1871. 



This geuus only differs from the last iii possessing two conic tubercles 

 of the inner series on the last superior molar, instead of one, a charac- 

 ter first pointed out by Marsh. 



LiMNOHYUS PALUDOSUS, Leidy. 



Proceedings Academy of Natural Sciences, Phialdelphia, 1870, p. 113, not of later 



descriptions. 



My expedition did not obtain any specimens which I can as yet certain- 

 ly refer to this species. The measurements given b}' Professor Marsh for 

 his Palccosyops laticeps approach very nearly to this one. Thus the 

 width of the crown of the last superior molar is M. .038; in P. latice])s- 

 .040 ; in L. diaconus, Cope, it is .047. 



LiMNOHYUS DIACONUS, Cope. 



Pdloeosyops diacoims, Cope, ou some Eocene Mammals obtained by Havden's Geological 



Survey of 1872, 1873, p. 4. 



The species is as large as the Palccosyops major of Leidy, but differs 

 in the relative proportions of the teeth. Thus the last three molars have 

 the same antero-posterior length, while the space occupied by four pre- 

 molars is shorter. The anterior and posterior ciugula of the true molars 

 are very strong, but it is uot well marked on the inner side between the 

 cones. The latter are acutely conic, and the median anterior tubercle 

 is strongly developed. Although the wearing of the teeth indicates 

 maturity, the enamel is coarsely and obtusely rugose. The fourth pre- 

 molar differs from that of L. major in its smaller size relatively and 

 absolutely, and in the presence of a prominent vertical tubercle on the 

 outer face, rising to the angle of the deep notch between the lobes. The 

 third premolar is as wide as the fourth, and about as large as the cor- 

 responding tooth in L. major, but different from it in the absence of 

 tubercle and ridge that mark its external face. The first premolar has 

 two roots, and the canine is large and stout. 



This large Palajotheroid is represented by parts of the two maxillary 

 bones, which present the crowns of the third and fourth i^remolars, and 

 of the second and third true molars, with the bases of the other molars 

 and i3remolars. 



Measurements. 



M. 



Length of entire molar series 0. 1710 



Length of true molars 10(30 



Length of last molar, (crown) 0420 



Width of last molar, (crown) 0473 



Length second molar 03.")0 



Length fourth premolar 02G0 



Width fourth premolar 02*30 



Width third premolar 0200 



Length third premolar 0200 



Diameter of basis of cauine 02t33 



The L. j^ci^itdosus, Leidy, is similar to this species in therugosity of the 

 enamel of its teeth, but appears by the measurements to be distinctly 

 smaller, so as to relate to it about as to P. major. 



as G s 



