184 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



lary; (3) the absence of a double cone on m^ In many other 



respects it resembles M. diploconus, especially in its proportions. 



It is distinguished from M. megarhimis by (1) the elongate 



premaxillary symphy- 

 sis, correlated with the 

 long, narrow facial re- 

 gion; (2) the narrowness 

 of its occipital condyles. 

 It is distinguished from 

 M. fluviatilis by (1) its 

 greatly superior size 

 and (2) the lesser prom- 

 inence of the orbits. 



Etymolo g y. — 

 Named "in honor of 

 Charles Earle, the 

 first monographer of 

 the genus Palaeo- 

 syops and its allies." 

 (Osborn.) 



Present determina- 

 tion. — The species 

 is probably valid. 

 (See p. 426.) 



Dolichorhinus interme- 

 dius Osborn, 1908 



Cf. Dolichorhinus inter- 

 niedius Osborn, this 

 monograph, page 405 



Original refer- 

 ence. — Am. Mus. 

 Nat. Hist. Bull., vol. 

 24, p. 611, fig. 15, 

 1908 (Osborn, 

 1908.318). 



Type locality and 



Top view. Am. Mus. 1837. After Osborn, 1908. neoloqic llOrizOn. — 

 One-fourth natural size. .^t. , -r» • i.^ 



Umta Basin, north- 

 eastern Utah; Eobasileus - Dolicliorhinus zone 

 (Uinta B 2). 



Hohtype. — A skull with dentition (Am. Mus. 1837), 

 discovered by the American Museum expedition of 

 1894. (See fig. 125.) 



Specific characters. — Osborn writes : 



Distinguished from D. hyognathus Scott and Osborn by (1) 

 its inferior size (pm'-m^ 179, m'-m' 109 mm.); 

 (2) premolars less progressive, with subconic 

 deuterocones; (3) all oingula less robust; (4) 

 nasals more pointed and less expanded distally; 

 (5) infraorbital shelf of malar relatively narrow. 



Etymology. — "The name 'intermedins' 



is given because in some characters this 



species is intermediate between Mesati- 



rhinus petersoni and DolichorMnus Tiyo- 



gnathus, although on the whole it is Figure 126. — Type (holotype) skull of Telmatheriiim ultimum 



much more nearly allied to the latter." side ™w. Am. Mus. 2O6O. After Osbom, 19O8. One-flfth natural size. The skull has been some- 

 //-j V s what deformed by pressure. 



Present determination. — The generic reference ap- I pointed. P,, pz laterally compressed, nonmolariform; ps, p4 

 pears certain; the species is probably valid. (See submolariform; dolichocephalic, anterior portion of face 

 p. 405.) I elongate. 



Figure 125. — Type (holotype) skull of 

 Dolichorhinus inter medius 



Telmatherium ultimum Osborn, 1908 



Cf . Telmatherium ultimum Osborn, this monograph, page 345 



Original reference. — Am. Mus. Nat. Hist. Bull., 

 vol. 24, p. 613, fig. 17, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Uinta Basin, 

 northeastern Utah; Diplacodon-Protitanotherium-Epi- 

 hippus zone (Uinta C, lower levels). 



Holotype. — A well-preserved skull with dentition 

 (Am. Mus. 2060). Discovered by Mr. Peterson, of 

 the American Museum expedition of 1895. (See fig. 

 126.) 



Synonymy. — This species was mentioned by Mat- 

 thew as Palaeosyops ultimus Osborn MS. (see p. 177), 

 but as no type was indicated or specific diagnosis 

 given the name remained a nomen nudum until a type 

 was designated and a diagnosis given by Osborn in 

 1908. 



Specific characters. — Osborn writes: 



P'-m*, 226 mm. Lateral superior incisors greatly en- 

 larged, caniniform. Pm^- ^. * with Internal subcrescentic 

 deuterocone ridges, with faint rudiments of tetartocones 

 posteriorly. Ectolophs of premolars elevated and biconvex. 



Etymology. — ultimus, latest. "The specific name is 

 given because this appears to be the last representative 

 of the Palaeosyops-Limnohyops-Telmatherium group." 

 (Osborn.) 



Present determination. — This species is certainly a 

 valid one. The grounds for regarding it as allied to 

 the genus Telmatherium are given on page 345. 

 Telmatherium? altidens Osborn, 1908 

 Cf . Telmatherium altidens Osborn, this monograph, page 351 



Original reference. — Am. Mus. Nat. Hist. Bull., 

 vol. 24, p. 614, fig. 18, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Uinta Basin, 

 northeastern Utah; Diplacodon-Protitanotherium-Epi- 

 hippus zone (Uinta C). 



Holotype. — A lower jaw with dentition (Am. Mus. 

 2025) discovered by the American Museum expedition 

 of 1895. (See fig. 127.) 



Specific characters. — Osborn writes: 



Pmj-mj, 330 milUmeters; a wide diastema (70 mm.) behind 

 the canines. Canines in male exceptionally elevated (76) and 



