334 



recent description and figures of the skull, it appears to me to be a larger 

 species of* Uintatherium than the U. robustum, but not of a distincl genus. 



The remains, which were first noticed by Professor Marsh and referred to 

 Titanotherium (?) anceps, subsequently to Mastodon anceps, and finally to 

 Tinoceras anceps, I have not seen. I have suspected that perhaps they 

 might pertain to the same animal as that I have described as Uintatherium 

 robustum. Should this prove to be the case, as the specific name of anceps 

 is of earliest date, the latter would be correctly designated as Uintatherium 

 anceps. 



Professor Marsh regards the Eobasileus s. Loxolophodon cornutus, Cope, as 

 pertaining to Tinoceras, probably T. grandis, Marsh, (Am. Jour. Sc. April, 

 1873.) On the other hand Professor Cope refers Dinoceras to Uintatherium, 

 and also includes as synonyms Titanotherium (?) anceps, and therefore Tinoceras, 

 Marsh, (Pr. Am. Phil. Soc. 1873.) Thus the conjoint views of these authors 

 rather .favor the idea that all are probably of the same genus. 



Since the article on Uintatherium robustum, page 96, was printed, I have 

 attempted a restoration of the skull in Fig. 1, Plate XXVIII, on an enlarged 

 outline taken from Professor Marsh's Fig. 1, Plate II, of Dinoceras mirabilis, 

 published in the American Journal of Science for February, 1873. The 

 cranial fragment and that of the upper jaw with the last molar tooth are 

 taken from the same skull as the specimens of Fig. 8, Plate XXV, and 

 Fig. 1, Plate XXVI. The canine is from the same specimen as Fig. 1, Plate 

 XXV. 



In the May number of the American Journal of Science for 1873, Pro- 

 fessor Marsh has indicated what he considers to be a new species of Dinoceras 

 with the name of D. lucaris. In the account he observes, " From Uintatherium, 

 so far as that genus is at present known, Dinoceras differs in the position of 

 the occipital condyles, in the more anterior position of the posterior horns, 

 and in the last molar, which lacks the external cone between the two trans- 

 verse ridges, and has a second small tubercle behind the posterior ridge." 

 These characters may, perhaps, together with others more important, point 

 to a different species, but appear hardly sufficient to distinguish a genus. 

 The differences are also more apparent than real ; for instance, the so-called 

 " external cone between tEe two transverse ridges" of the last molar, as seen 

 in Fig. 7, Plate XXV, is nothing more than a tubercle produced from the 

 basal ridge, might be absent in another individual, and is actually so in the 

 molar in advance, as seen in Fig. 12 of the same Plate. 



