31 



entire, but the canines, of which one is represented in Figs. 2, 3, arc broken 

 off at the crown. Tlie specimen pertained to an individual past maturity, as 

 indicated by the worn condition of the teeth. Tiie enamel is ai)radcd from 

 the summits of the outer lobes of the last premolar and the molars and the 

 summits of the inner lobes of the first molar, so as to expose tracts of den- 

 tine. Elsewhere the enamel is worn smooth, but remains of its original 

 rugose condition are yet visible in the last molar. In anatomical character 

 and proportions the teeth agree in all respects with those corresponding 

 among the specimens above described. 



The molar series consists of seven teeth which successively increase in 

 size from first to last. The molars or true molars approach in character those 

 of Titanotherium, and in a less degree those of Anoplotherium and Chalico- 

 therium. The crown is broad and low and rather rhombic in outline. It is 

 composed of four principal lobes expanding in a common base. The outer 

 lobes are the larger and have the shape so common in many allied animals as 

 Palisotherium, Ancliitherium, Anoplotherium, Oreodon, Cervus, &c. They 

 are three-sided pyramids with crescentoid summits, the anterior extensions of 

 wliich form stout external buttresses to the crown. The inner lobes are 

 broad cones less prominent than the outer lobes. Tlic anterior is the larger, 

 and is situated opposite the angular recess of the outer lobes; the posterior 

 occupies a position opposite the postero-internal face of the contiguous outer 

 lobe at the inner back corner of the crown. 



A strong basal ridge occupies the fore part of the crown, and elements of 

 the same are found at the bottom of the outer faces of the external lobes. A 

 tubercle exists in the angular interval of the anterior lol)es and the basal 

 ridge in front, which looks as if it were the rudiment of the large antero-in- 

 ternal lobe in Anoplotherium and its homologue in ordinary ruminants. 



In the last molar the postero-internal Ipbe, as existing in the molars in ad- 

 vance, is absent or is substituted by a small tubercle extending outwardly as a 

 posterior basal ridge to the crown. 



In the unworn condition of the upper molars of PalfEosyops the external 

 lobes of the crown have acute crescentoid summits which conjoin on the sum- 

 mit of the median outer buttress. As the teeth were worn away in mastica- 

 tion, a W-shaped tract of dentine appeared on the outer lobes, and this gradu- 

 ally widened with the progress of abrasion. As the summits of the inner 

 lobes were worn away, circular islets of dentine made their appearance, 



