196 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Etymology. — Named in honor of Prof. H. F. Osborn. 



Present determination. — The genus is doubtfully sep- 

 arable from Diplacodon Marsh, but the species differs 

 in the more advanced development of the third upper 

 premolar. 



FiGUKE 147. — Type (holotype) of Lambdotherium progressum 

 Lower jaw. Am. Mus. 14917. After Osborn, 1913. Natural size. 

 Heterotitanops Peterson, 1914 

 Cf. Metarhinus, this monograph, page 420 

 Original reference. — Carnegie Mus. Annals, vol. 9, 

 Nos. 1-2, pp. 53-57, text figs. 1, 2; pi. 11, "issued 

 August 17, 1914" (Peterson, 1914.2). 



Type species. — Heterotitanops parvus Peterson. 

 Generic characters. — Peterson writes: 



Dentition: If?, C-}-?, P|?, M|. Deciduous dentition: If?, 

 C-r, Mf?. Rapid increase in size of the deciduous upper 

 cheek teeth from first to last tooth. D * with perfectly formed 

 internal tubercles (proto- and hypocones) and the antero- 

 external angle very greatly developed. Molars hypsodont. 

 Ml with large conical proto- and hypocones, the external faces 

 of the ectoloph less emarginated anteroposteriorly 

 than in the titanotheres generally and the median 

 vertical ridge of the ectoloph projecting forward to a 

 greater degree. 



Etymology. — erepoj, other, different; Ttrdi', 

 Titan; ajf, face; in allusion to its supposed 

 possible relationship to such forms as Eoti- 

 tanops. 



Present determination. — According to Dr. 

 W. K. Gregory, who has studied the type 

 specimen of Heterotitanops parvus, the animal 

 probably represents a very young individual of 

 Metarhinus or Rhadinorhinus. 



Heterotitanops parvus Peterson, 1914 



Cf. Metarhinus sp. or Rhadinorhinus sp., this mono- 

 graph, page 198 



Original reference. — Carnegie Mus. Annals, 

 vol. 9, Nos. 1-2, pp. 53-57, text figs. 1, 2, 

 pi. 11, 1914; "issued August 17, 1914" 

 (Peterson, 1914.2). ^"'""'° 



Type locality and geologic horizon. — White River, 

 Uinta County, Utah; base of Metarhinus zone (Uinta 

 B 1). The type specimen "was found articulated 

 in a hard sandstone concretion, and lower down in 

 horizon A ['^J of the Uinta sediment than any mam- 



" The upper or fosslliferous part of Uinta A of previous reports is Uinta B 1 of 

 this monograph. 



malian remains hitherto described from that forma- 

 tion." (Peterson.) 



Type. — Skull, lower javrs, vertebral column, ribs, 

 limb bones, calcaneum, and astragalus of young indivi- 

 dual (Carnegie Mus. 2909). (See figs. 150, 151, 152, 360.) 

 Specific characters. — Not determined. 

 Etymology. — parvus, poor, small. 

 Present determination. — According to Dr. W. K. 

 Gregory the type specimen probably represents a 

 very young individual of an undetermined species of 

 one of the previously described genera of Uinta 

 Basin titanotheres, probably of Metarhinus. 



Eotitanotherium Peterson, 1914 



(To replace Diploceras Peterson, 1913, preoccupied) 

 Cf. Eotitanotherium, this monograph, page 435 



Original reference. — Carnegie Mus. Annals, vol. 9, 

 p. 220, September 12, 1914 (Peterson, 19U.4); Eotitano- 

 therium, a new generic name to replace Diploceras 

 Peterson. (See Peterson, 1914.1.) 



In my article entitled "A new titanothere from the Uinta 

 Eocene" I employed the generic name Diploceras, having 

 overlooked the fact that this name is already preoccupied, 

 having been employed by Conrad as early as 1844 to designate 

 a genus belonging to the Mollusca. For this name I now sub- 

 stitute the name Eotitanotherium, which, after a diligent search 

 of the literature, I believe is not preoccupied. (Peterson.) 



Etymology. — ^cos, dawn; Ttrav, a Titan; drjpiov, a 

 beast. 



FiGUEE 148. — Type of Diploceras osborni 

 I lower jaw. Carnegie Mus. 2859. After Peterson, 1914. One-fourth natural size. 



Present determination. — The genus is doubtfully 

 separable from Diplacodon Marsh. 



Telmatherium? birmanicum Pilgrim and Cotter, 1916 



Cf. Telmatherium f birmanicum, this monograph, pages 196-199 

 Original reference. — India Geol. Survey Records, vol. 

 47, pt. 1, pp. 72-74, pi. 5, figs. 9-11, 1916 (Pilgrim and 

 Cotter, 1916.1). 



