30 



were received from Professor II ay den, obtained on Henry's Fork of Green 

 River, Wyoming, which are referred to in the last paragraph of the same 

 article of the Proceedings above mentioned as the former ones. The addi- 

 tional specimens consist of several small jaw-fragments, with teeth, belonging 

 to an individual past maturity, as indicated by the worn condition of the 

 latter. 



One of the specimens, a much-worn last upper premolar, is represented 

 in Fig. 4, Plate V. It agrees with the corresponding tooth above described 

 both in form and proportions. The summits of the three lobes of the crown 

 arc worn down so as to expose large tracts of dentine. 



A second specimen consists of an upper-jaw fragment retaining a portion 

 of the first molar and the complete second one. The former was so much 

 worn as to have a great part of the enameled triturating surface removed.. 

 The second molar, represented in Figs. 8, 9, Plate V, has a. low trapezoidal 

 crown composed of four lobes, of which the anterior two agree in constitu- 

 tion and proportions with the fragment of the corresponding tooth above 

 described. The outer pair of lobes are crescentoid pyramidal and bounded 

 externally by strong convex buttresses. The inner lobes, of which the an- 

 terior is much the larger, form broad cones. A strong basal ridge bounds 

 the crown in front. The enamel is worn smooth and is abraded from the 

 summits of the outer lobes so as to expose broad dentinal tracts. The fore 

 and aft diameter of the crown of the second upper molar is 16J lines ; its 

 transverse diameter is 18 lines. The remaining specimen consists of an 

 upper-jaw fragment containing the last molar, represented in Figs. 6, 7, 

 Plate V- The tooth is fractured and its parts somewhat dislocated, so as to 

 extend its breadth. It has the same constitution as the former tooth, except 

 that it has but a single internal lobe, which in great part is broken away in 

 the specimen. 



Many more complete specimens referable to PalcEosyops paludosus have 

 been received from Drs. Carter and Carson. One of the most important of 

 these consists of the facial portion of a skull containing nearly all the - molars 

 and the canines of both sides. The specimen submitted to my examination 

 by Dr. Carter, represented in Fig. 51, Plate XVIII, was discovered in a 

 greenish friable sandstone of the Grizzly Buttes. The face is entirely broken 

 away at its upper part and fore extremity. The molar teeth, of which a full 

 series is represented in Figs. 3, 4, Plate IV, are for the most part preserved 



