198 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



One of the most crucial points which has presented itself to 

 us for decision in connection with the material belonging to this 

 species is the position in the jaw of the tooth (G. S. I. No. C. 



widening which we must assume to have taken place in m' of 

 this species. Again the faint V-ing of the line which connects 

 the two external crescents points to these being more closely 



FiGUEE 150. — Type (holotype) skeleton of Heterotitanops parvus 

 Carnegie Mus. 2909. After Peterson, 1914. One-fourth natural size. 



315) figured in Plate 5, Figure II. Although in some respects 

 this specimen reminds us of the last upper molar in some of the 



FiGtTBE 151. — Type (holotype) skull of Heterotitanops parvus 



Carnegie Miis. 2909. After Peterson, 1914. One-half natural size. 



upper Eocene members of the Palaeosyopinae, yet its small 



size as compared with the two other specimens of the upper 



connected than is the case in the last upper molar of a titano- 

 there. On the other hand these features are such as the last 

 upper premolar of that family 

 would present, the only peculiar- 

 ities being the rounded nature of 

 the inner cone and the highly de- 

 veloped cingula on the anterior 

 and posterior margins of the frag- 

 ment, dying away internally and 

 apparently also on either side of 

 the two main external cusps. 



It is evident that this simple struc- 

 ture of pm* prohibits the possibility 

 of this species being one of theTitan- 

 otheriinae of the Oligocene, while 

 on the other hand the increased 

 development of the cingulum and 

 the absence of an intermediate 

 tubercle point to its representing one of the latest develop- 

 mental stages of the Eocene subfamily of the Palaeosyopinae. 

 A similar indication is afforded by the fragmentary upper 



Figure 152. — Type (holo- 

 type) of Heterotitanops 

 parvus 



Upper and lower teeth. Carnegie 

 Mus. 2909. After Peterson, 

 1914. 1, Deciduous upper pre- 

 molars, first permanent molar; 

 2, permanent mi. One-half 

 natural size. 



Figure 153. — Cotypes of Telmatherium? birmanicum 



In the collection of the Geological Survey of India. After Pilgrim and Cotter, 1916. Naturalsize. A, "The antero-internal 

 portion of a right upper molar, surface view"; B, "e-xternal portion of an upper molar, showing the gently rounded 

 median fold, external view"; C, "internal portion of last upper premolar, surface view." 



molars militates against this view. Further, the almost 

 rectangular shape of the inner portion of the tooth, which 

 alone is preserved to us, is inconsistent with the external 



molars, in which the protocone is rather lofty and the only 

 vestige of a protoconule is the presence of a minute row of 

 fringing the protocone between it and the paracone. 



