180 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Limnohyops priscus Osborn, 1908 



Cf. Limnohyops priscus Osborn, this monograph, page 306 



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

 vol. 24, pp. 601-602, fig. 5, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Grizzly Buttes, 

 Bridger Basin, Wyo.; Palaeosijops paludosus-Oroliippus 

 zone (Bridger B 2). 



A 



Figure 114. — Type (holotype) of Lambdotherium 

 primaevum 



Amherst Mus. 254. After Loomis, 1907. A, Right upper molars 1 and 

 2; B, right lower molars (mi-ms). Natural size. 



Holotype. — A crushed skull with excellent dentition 

 (Am. Mus. 11687), discovered by the American 

 Museum expedition of 1903. (See fig. 115.) 



Figure 115. — Type (holotype) of Limnohyops priscus 

 Am. Mus. 11687. Pi-m' left. After Osborn, 1908. One-half natural size. 



Characters. — Osborn writes: 



P'-m', 148 (type) to 161 millimeters. Distinguished from 

 the contemporary Limnohyops laevidens Cope by its larger 

 size and by the more progressive character of pm^-pm'. 

 Second superior premolar obliquely elongate with a very rudi- 

 mentary tritocone. Large hypocone on m'. 



Etymology. — priscus, ancient, in allusion "to the 

 low geological level and primitive characters of this 

 species." (Osborn.) 



Present determination. — The species and generic 

 reference are probably valid. (See p. 306.) 



Figure 116.- 



-Tj'pe (holotype) skull of Limnohyops 

 matthewi 



Am. Mus. 11684. After Osborn, 1908. One-fourth natural size. 



Limnohyops matthewi Osborn, 1908 



Cf. Limnohyops matthewi Osborn, this monograph, page 308 



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

 24, p. 602, fig. 6, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Grizzly Buttes, 

 Bridger Basin, Wyo. ; Palaeosyops paludosus-Orohippus 

 zone (Bridger B 2). 



Holotype. — A skull (Am. Mus. 11684) lacking the 

 anterior portion and dentition. Discovered by the 

 American Museum expedition of 1903. (See fig. 116.) 



Specific characters. — Osborn writes: 



Intermediate in size between L. laevidens and L. monoconus. 

 M' of small size with large hypocone and quadrate inner half 

 Occiput very high and narrow. Cranial portion of skull greatly 

 abbreviated, bringing post-tympanic and postglenoid processes 

 into broad union. Temporal openings subcircular as defined 

 by zygomatic arches. 



Etymology. — Named "in honor of Dr. W. D. 

 Matthew, of the American Museum staff." (Osborn.) 



Present determination. — The species is probably 

 valid. (See p. 308.) 



Figure 117. — Type (holotype) skull of Limnohyops monoconus 

 Am. Mus. 11679. After Osborn, 1908. One-fourth natural size. 



Limnohyops monoconus Osborn, 1908 



Cf. Limnohyops monoconus Osborn, this monograph, page 309 



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

 24, p. 603, fig. 7, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — Grizzly Buttes, 

 Bridger Basin, Wyo. ; Palaeosyops paludosus-Orohippus 

 zone (Bridger B 2). 



Holotype. — A crushed skull with dentition (Am. 

 Mus. 11679). Discovered by Mr. Quackenbush, of 



