58 



Palaeosyops possessed but a single cone lo the inner pari of the crown, the 

 name subsequently proposed by Professor Marsh on account of this character- 

 istic was untenable. Under these circumstances, though I previously viewed 

 the difference as simply specific, I would adopt the generic name of Limnohyus 

 Cor those forms of Palaeosyops, as recognized by the general constitution of 

 the teeth, in which the last upper molars have two cones to the inner part of 

 the crown. 



Fig. 13, Plate XXIII, represents an upper molar tooth, apparently the first 

 of the series of true molars, resembling in form the corresponding teeth of 

 Palceosyops paludosus. The enamel of the tooth is, however, comparatively 

 smooth, a condition which is clearly independent of its age, as the tooth is 

 but moderately worn. As a considerable degree of variation is observed in 

 the extent of wrinkling of the enamel of the teeth of Palceosyops paludosus, 

 independent of wearing, it is not improbable the specimen may pertain to 

 an individual variety of the same, though it probably may indicate another 

 species. 



The specimen was found by Dr. Corson in association with the large tusks 

 originally referred to TJintamastix atrox, described in a later chapter, and 

 represented in Figs. 1 to 3, Plate* XXV. 



Since writing the description of the smooth, enameled molar tooth, Pro- 

 fessor Marsh, who has inspected the specimen, informs me that it pertains to 

 the same animal he has described under the name of Palceosyops Zaticeps, 

 (Am. Jour. Sc., Aug., 1872.) As this is stated to have four lobes to the 

 crown of the last upper molar, for reasons already given, it would belong to 

 the genus Limnohyus. 



Fig. 8, Plate XXIV, represents the crown of an upper molar tooth, which 

 was found, together with some small fragments of other molars, both upper 

 and lower, by Dr. Corson on the buttes of Dry Creek Canon. The specimen 

 I supposed to belong to a small species of Palaeosyops, and so referred it, 

 under the name of P. humilis, in a letter to the Academy, published in 

 its Proceedings for July 30, 1872. Under the impression that it was 

 perhaps the last tooth of the series, in view of the distinction suggested by 

 Professor Marsh between Palaeosyops and Limnohyus, I subsequently 

 ascribed it to the latter. Professor Marsh informs me-that he has a number 

 of specimens which lead him to regard, the tooth as pertaining to the tempo- 

 rary series of Palaeosyops. 



