32 Field Museum of Natural History — Geology, Vol. IV. 



To the present writer the abandoning the name of D. comulus, the 

 original type of the genus, appears undesirable. This species is based 

 upon a well-preserved skull with characteristics easily recognizable. 

 It appears to the writer to be a direct successor of D. longiceps which 

 is now traced through the upper half of Horizon A and lower Horizon B . 

 The two species apparently represent a line of titanotheres indigenous 

 to the Uintah formations. D. hyognathus, with which D. cornutus has 

 been made synonymous, is a Washakie species based upon an isolated 

 mandible.* No skull associated with a similar mandible has been 

 described. The mandible indicates a much larger individual than the 

 type of D. cornutus. The relative length of the molar-premolar series 

 (208:245 mm.) in the types of the two species indicates a considerable 

 disparity in size. There are also apparent differences in proportions. 

 In view of the variation in this genus and the number of species re- 

 ferred to it, it would appear unwise to correlate the two species until 

 an associated skull and mandible referable to the one or the other species 

 is known. 



D. intermedius\ Osborn. 



Type specimen, No. 1837 Amer. Mus. 



Type locality: Uintah B (after Peterson). 



This is apparently the smallest member of the genus described from 

 the Uintah formations. So far as the writer is able to determine, no 

 specimen in the Museum collection is referable to this species. 



1 D. heterodon\ Douglass. 



Type specimen, No. 2340 Carnegie Museum. 



Type locality : Upper Uintah B or lower C (after Peterson) . 



This form as illustrated presents the characters of a somewhat spe- 

 cialized Dolichorhinus with the posterior narial opening in the primary 

 position as in Mesatirhinus. Further comparison between this species 

 and the type of D. intermedius is needed in order to determine their 

 relationships. 



D. longiceps% Douglass. 



Type specimen, No. 12 167 Carnegie Museum. 



Type locality : Uintah B (after Peterson) . 



Four skulls (Nos. 12175, 12182, 12193, 12200 Field Mus.) collected 

 by the Museum expedition from the Upper Metarhinus Beds are refer- 



* Scott & Osborn, Trans. Amer. Phil. Soc. Vol. XVI, p. 513. Earle, Jour. 

 Acad. Nat. Sci. Phila., Vol. IX, p. 348, PI. II. 

 t Bull. Am. Mus., Vol. XXIV. 

 § Annals Carnegie Mus., Vol. VI, p. 310. 

 % Op. cit., p. 312, 1909. 



