C6 ARCHAEOTHERIUM. 



Arcliaeotlieriiiin {Entchdon?) robtistiiui, Leidy. 



(Plate X., Figs. 8-13.) 

 Arciodon, Leidy: Proc. Acad. Nat. Sci., 1851, v. 278. 

 Archaeoiherium rolus/um, Leidy: Owen's Rep. of a Geol. Surv. of Wise, etc., 572. 



This species is proposed upon fragments of the crowns of the posterior two 

 niohxrs of the left side, and a portion of the crown of a canine tooth probably of 

 the left side inferiorly. 



These specimens, which belong to the collection obtained by Mr. T. A. Culbert- 

 son, I at first supposed indicated the existence of a genus allied to the Bear; but 

 by comparison, they have since been determined to belong to a species of Archaeo- 

 tlurium larger than that described in the preceding pages. 



The fragments of molars (X. 10-13) are almost identical in their form with 

 the corresponding portion of the same teeth of Archaeoiherium Morloni, except that 

 in the last molar the posterior basal ridge rises into a conical eminence or fifth 

 lobe, which is more regular, but less prominent, and more expanded at the base than 

 those in advance. The teeth have been almost a fourth larger than those corre- 

 sponding of Archaeotherlum Mortoni. 



The fragment of the crown of a canine (8, 9) resembles more that of the Bear 

 than that of any existing ungulates. It is curved conical in form, and presents a 

 slight longitudinal ridge defining its outer and inner faces. It is completely covered 

 with enamel, which is thinnest at the inner face, and is unworn in the specimen. 



