DISCOVERY OF THE TITANOTHEEES AND ORIGINAL DESCRIPTIONS 



231 



Specific characters. — Toula's description is too long 

 to quote here. The principal characters revealed by 

 his figures are, symphysis massive, canines (?) large, 

 four lower premolars, lower molars with faint external 

 cingula, hypoconulid of ms without strong internal 

 crest. 



Etymology. — rumelicus, in allusion to Rumelia, the 

 region in Hungary where the type was discovered. 



Present determination. — The species is probably 

 valid, and its generic reference is probably to 

 Brontotherium. 



SPECIES DESCRIBED BY OSBOEN IN 1896 AND 1902 

 Titanotherium ramosum Osborn, 1896 



Cf. Brontotherium ramosum, this monograph, page 577 



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

 vol. 8, p. 1941, pi. 4, text fig. 13, 1896 (Osborn, 

 1896.110). 



Type locality and geologic horizon. — "Upper 

 Titanotherium beds, South Dakota." Chadron for- 

 mation, Quinn Draw, Big Badlands, S. Dak. 



Type. — A complete male skull lacking incisive 

 border. Am. Mus. 1447. (See fig. 194.) 



Characters of type. — Osborn writes: 



The distal spreading or branching of the horns is the 

 character by which this species is designated. It differs 

 from T. elatum in this character, but more especially in 

 the great depth of the "connecting crest" and the ex- 

 treme flattening of the horns, the section, as shown in 

 diagram 1, being intermediate between that of the T. 

 elatum and of T. plaiyceras. It is remarkable that the 

 teetli in this large skull are relatively of 3mall size; the 

 last upper molar has no second cone. 



Etymology. — ramosum, branched, in allusion to 

 the "distal spreading or branching of the horns." 



Present determination. — The species is probably 

 valid. 



Megacerops brachycephalus Osborn, 1902 



Cf. Brontops brachycephalus, this monograph, page 483 



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

 vol. 16, pp. 97-98, fig. 3 (not the type), 1902 

 (Osborn, 1902.208). 



Type locality and geologic horizon. — Big Bad- 

 lands, S. Dak.; Chadron formation, Chadron A, base 

 or level A of lower Titanotherium zone. 



Type. — A complete skull (Nat. Mus. 4261, skull a), 

 collected by J. B. Hatcher in 1887. (See fig. 195.) 



Specific characters. — Osborn writes: 



The type of this species is No. 4261, U. S. Nat. Mus. It 

 includes very small, broad-skulled titanotheres with very rudi- 

 mentary second internal cones upon the upper premolars; 

 nasals elongate, narrowing anteriorly, as in Palaeosyops. Horns 

 of anteroposterior oval section placed above orbits. It is 

 represented in the National Museum by numerous skulls 

 besides the type, all collected and recorded by Hatcher. One 

 of these skulls was provisionally referred by him to Teleodus avus, 

 from which this species is quite distinct. 



Etymology. — /3paxi's, short; Ki4>a\i), head, in allusion 

 to the brachycephalic form of the skull. 



Present determination. — The species is probably 

 valid. 



Megacerops bicornutus Osborn, 1902 



Cf. Diploclonus bicornutus, this monograph, pages 234, 501 



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

 vol. 16, p. 99, fig. 5, 1902 (Osborn, 1902.208). 



Figure 191. — Type (holotype) skull of Titanops medius 

 After Marsh. Nat. Mus. 4256. One-eightli natural size. 



Type locality and geologic horizon. — Quinn Draw, 

 White River, S. Dak.; exact level not recorded. Col- 

 lected by J. W. Gidley, 1896. 



Type. — Skull and lower jaws (Am. Mus. 1476). 

 (See fig. 196.) Paratype, skull (Am. Mus. 1081). 

 One of these skulls (No. 1081) was first described by 

 Osborn (1896.110, p. 176) as Titanotherium torvum ox 

 rohustum. 



Specific characters. — Osborn writes: 



Horns directed anteriorly. Hornlets upon the inner and 

 anterior midportion of the horn. Basal section of the horn 

 slightly oval, subtransverse. Nasals narrow and relatively 

 elongate. Sharp malar bridge in front of orbit. Orbit large. 



