EVOLUTION OF THE SKULL AND TEETH OF EOCENE TITANOTHERES 



363 



Bridger C or D: Skull of a very old male (Am. Mus.) 1545 

 found on Henrys Fork. Basilar length, 523 millimeters; 

 pi-m', 197; large fanged, recurved canines. Horn rudiments 

 rugose. 



Bridger C or D: Skull, jaw, and parts of skeleton of a male 

 adult, with open sutures (Am. Mus. 1587) from Henrys Fork. 

 Affords characters of the feet. 



Bridger D 2: Skull, jaws, and parts of skeleton (Am. Mus. 

 12204). Basilar length estimated at 490 millimeters. Probably 

 a male, aged. Grinding teeth relatively small. Affords 

 knowledge of the femur and part of the feet. 



Bridger C 5: Very old female skull (Am. Mus. 12678). The 

 first superior molar of both sides has dropped out. Canines 

 short, recurved, cingulate posteriorly. Basilar length, 500 



2. Manteoceras washakiensis Osborn 



Washakie A (upper levels) : Crushed but complete skull (Am. 

 Mus. 13165) from the base of Haystack Mountain, summit of 

 the brown sandstone, or upper part of Washakie A. A female 

 with relatively small, obtuse, recurved and posteriorly cingulate 

 canines. Horn rudiments slightly defined. Grinding series, 

 pi-m^, 200 millimeters. 



3. Manteoceras sp. 



Washakie B : Of the three specimens or cotypes described by 

 Cope as Palaeosyops vallidens, the jaws (Am. Mus. 5098) from 

 Mammoth Buttes appear to belong to Manteoceras sp. indet. 

 The other cotype (upper teeth) is referred to Dolichorhinus (see 

 below) . 



Figure 303. — Skulls of Manteoceras manteoceras 

 One-fourth natural size. A, Top view; Am. Mus. 1587, Henrys Fork, Bridger Basin, Wye, upper (?) levels. B, Palatal view, chiefly from Am. 

 IVlus. 2353, south of Haystack Mountain, Washakie Basin, Wyo., lower beds; partly restored from Am. Mus. 1570, La Clede, Washakie Basin; some 

 details and sutures from a specimen now in the National Museum, formerly Am. Mus. 1545, Bridger Basin. 



millimeters; zygomatic breadth, 294 (estimated); p'-m^, 187. 

 Equal in size to palate from the upper portion of Washakie A. 



Washakie A: The type skull of the species (Am. Mus. 1569) 

 from the brown sandstones. Probably an aged male. Horn 

 rudiments prominent, slightly rugose. Estimated basilar 

 length 492 milhmeters; p'-m', 183. 



Washakie A: The type skull (Am. Mus. 1570). Adult male 

 skull, occiput lacking. P>-m', 186 millimeters. Agrees closely 

 in size with Am. Mus. 1511, from Bridger C or D. 



Washakie A: Skull with jaws (Am. Mus 2353) lacking pre- 

 maxillae. Zygomatic breadth, 274 millimeters. The grinding 

 teeth are of relatively small size (p'-m', 178 mm.). 



4. Manteoceras uintensis Douglass 



Uinta C (lower levels) : The anterior half of a skull (Carnegie 

 Mus. 2388), "from gray sandstone in red Uinta beds," the 

 type of M. uintensis. A large male; grinding series, 240 

 millimeters (see below). 



Synopsis of progressive characters in the three succes- 

 sive species of Manteoceras. — 1 . M. manteoceras: Levels, 

 Bridger C 2 to D and Washakie A. Skull of medium 

 size (basilar length 447-500+ mm.). Face relatively- 

 short; zygomata stout; horn swelling prominent. 



