DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



181 



the American Museum expedition of 1903. (See fig. 

 117.) 

 Specific characters. — Osborn writes: 



M^ without hypocone, roundly triangular in form, with 

 broadly extended ectoloph and parastyLe. P^-m' 150, p'-m^ 

 163 milUmeters. Condyle to incisive border 510. Occiput 

 very high, cranium relatively elongated, with space (4 miUi- 

 meters) between post-tympanic and postglenoid processes. 

 Temporal openings as defined by zygomatic arches elongate. 



Figure 118. — Type (holotype) skull of Palaeosyops leidyi 

 Inferior view. Am. Mus. 1544. After OsbDrn, 1908. One-fourth natural size. 



Etymology. — yibvo's, single; kccws, cone; named "in 

 reference to the presence of but a single cone on the 

 inner side of the third superior molar, an exceptional 

 condition in the genus Limnohyops." (Osborn.) 



Present determination. — The specific and generic 

 references are probably valid. (See p. 309.) 



Palaeosyops leidyi Osborn, 1908 



Cf. Palaeosyops leidyi Osborn, this monograph, page 323 



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

 vol. 24, p. 604, fig. 8, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Henrys Fork, 

 Bridger Basin, Wyo.; Uintatherium- Manteoceras- Mesa- 

 tirliinus zone (Bridger C 2 to C 4). Discovered by the 

 American Museum expedition of 1893, under Dr. 

 J. L. Wortman. 



Holotype. — A well-preserved skull (Am. Mus. 1544) 

 associated with considerable portions of the skeleton. 

 This specimen, which is associated with a considerable 



portion of the postcranial skeleton, is now mounted 

 in the American Museum, the missing parts having 

 been supplied from other individuals. (See p. 323; 

 Pis. XXVII, L, LXI; and fig. 118.) 

 Specific characters. — Osborn writes: 



Of larger size; total length of skull 415 millimeters; p'-m^, 158; 

 P2-m3, 168; diastema behind canines; p-', p^ superior, with 

 mesostyles. Barely defined sweUings representing the rudi- 

 ments of osseous frontonasal horns. 



Etymology. — Named "in honor of Joseph Leidy, 

 the discoverer of the family and [founder] of the 

 genera Palaeosyops, Titanotherium, and Megacerops." 

 (Osborn.) 



Present determination. — The species is probably 

 valid. 



Palaeosyops granger! Osborn, 1908 



Cf. Palaeosyops grangeri Osborn, this monograph, page 335 



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

 24, p. 604, fig. 9, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Twin Buttes, 

 Bridger Basin, Wyo. ; Uintatherium- Manteoceras- Mesa- 

 tirhinus zone (Bridger C 1). 



Holotype. — A palate and grinding teeth with por- 

 tions of the lower jaw and skull (Am. Mus. 12189), 

 American Museum expedition of 1904. (See fig. 119.) 



Specific characters. — Osborn writes: 



Exceeding P. robustus in certain dental proportions; p^-m^, 

 165 millimeters. Fourth superior premolar enlarged (trans- 

 verse, 31 mm.). Molars with extremely prominent parastyles 

 and oblique ectolophs. 



Etymology. — Named "in honor of Mr. Walter Gran- 

 ger, of the American Museum staff, whose explora- 

 tions have transformed our knowledge of the Bridger 

 animals. " (Osborn.) 



Present determination. — The species is probably 

 ^alid. (See p. 335.) 



Figure 119. — Tj'pe (holotype) of Palaeosyops grangeri 

 ; maxillary with p'-mi. Am. Mus. 12189. After Osborn, 1908. One-half natural size. 



Palaeosyops copei Osborn, 1908 



Cf. Palaeosyops copei Osborn, this monograph, page 336 



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

 24, p. 606, fig. 10, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Lone Tree Hen- 

 rys Fork, Bridger Basin, Wyo.; Uintatherium- Man- 

 teoceras-Mesatirhinus zone (Bridger D 3). 



Holotype. — A series of superior grinding teeth (Am. 

 Mus. 11708). (See fig. 120.) 



