706 THE BELDGEE FAUNA. 



Leidy described both genus and species. The species then described was, 

 however, diflPerent, according to Marsh's view, from the original P.jyaludosus. 

 By this accident, the second species had a generic and an eiToneous specific 

 name; and the earlier described species had a specific and no generic name. 

 Dr. Leidy supplied the latter deficiency in subsequently naming the genus 

 with two cones Limnohpus, a name already used by Marsh, and synony- 

 mous with Palososyops. To those who will not again use a name which has 

 become a synonyme this course would not appear judicious; for my own 

 part, I never saw any disadvantage to arise from such a course. As to the 

 second species, the Palceosyops without name, I called it Icevidens, thinking 

 it very inconvenient to have two ])aludosi in two so nearly allied genera. 



Besides the L. paludosus, there are two large species of Limnohpus, L. 

 laticeps Marsh, and L. diaconus Cope. The L. fontinalis Cope is a smaller 

 form. 



LiMNOHYUS DIACONUS Cope. 



Anunal Report U. S. Geological Survey Terrs., 1872 (1873), p. 593. Paloeoayopa diaconus Cope, PaliBon- 



tological Bulletin, No. 12, p. 4, March 8, 1873. 



Plate LI, fig. 3. 



This large species is represented by parts of the two maxillary bones, 

 which present the crowns of the third and fourth premolars, and of the sec- 

 ond and third true molars, with the bases of the other molars and premo- 

 lars. The third true molar is injured posteriorly, but enough remains to 

 show that it possessed two internal cones. 



The jaw is as large as the PalcBOsyops major of Leidy, but difiers in the 

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

 anteroposterior length, while the space occupied by the four premolars is 

 shorter. The anterior and posterior cingula of the true molars are very 

 strong, but it is not well marked on the inner side, between the cones. The 

 latter are acutely conic, and the median anterior tubercle is strongly devel- 

 oped. Although the wearing of the teeth indicates maturity, the enamel is 

 coarsely and obtusely rugose. The fourth premolar differs from that of the 

 four species of Palceosyops described, in its smaller size relatively and abso- 

 lutely, and in the presence of a prominent vertical tubercle on the outer 

 iace, rising to the angle of the deep notch between the lobes. It has a com- 



