DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



173 



ably the specimen figured in Leidy's memoir of 1873, pi. 5, 

 fig. 11] with this jaw, I find that there is such a marked difference 

 in some of its characters that I have to give it a specific rank. 

 The following characters distinguish it from Leidy's type: (1) 

 The great posterior extension of the jaw behind the last molar 

 (this is a unique character of this jaw — I have not observed it 

 in any other species of this subfamil}') ; (2) the symphysis is 

 much more elongated than in P. minor; (3) the lower border is 

 straighter and less inflected than in P. minor; (4) the posterior 



en'f 



Figure 108. — Earle's type of Palaeosyops longirostris 

 Princeton Mus. 1027-5. One-foarth natural size. 



tubercle of the last inferior molar is much larger than in the 

 last named species; (5) the V's of premolar 4 are not so well 

 developed as in P. ininor, and there is also a well marked dif- 

 ference in the size of the first molars of the two species. 



In this jaw the first true molar is con- 

 siderably smaller than in P. minor. The 

 canine is very large and semiprooumbent, 

 its position in the jaw resembling that of 

 T. hyognathus. 



Etymology. — longus, loia^g; rostrum, 

 bill, snout (hence, in this instance, 

 jaw); in allusion to the great 

 posterior extension of the j aw behind 

 the last molar. (Earle.) 



Present determination. — This prob- 

 ably valid species is certainly refer- 

 able to the Palaeosyopinae and 

 probably to Palaeosyops. (See 

 p. 319.) 



Telmatotherium diploconum Osborn, 1895 



Cf . Rhadinorhinus diploconus (Osborn) , this 

 monograph, page 431 



Original reference. — Am. Mus. 

 Nat. Hist. Bull., vol. 7, p. 85, fig. 6, 

 1895 (Osborn, 1895.98). 



Type locality and geologic horizon. — 

 NoTthe&sternlJtah;" Telmatotherium 

 cornutum" beds, Eohasileus-Doli- 

 chorhinus zone (Uinta B). 



Holotype. — "The type is a skull 

 (No. 1863) [Am. Mus.] in which the 

 nasals are wanting and the mid- 

 region of the cranium was ci'ushed." 

 (See fig. 109.) 



Characters. — Osborn writes: 



Superior premolar-molar series, 174 millimeters. A large 

 hypocone upon last upper molar. Nasofrontal without horn. 

 Long sagittal crest. Canines small, rounded. 



This species differs from T. megarhinum in the absence of the 

 infraorbital shelf and in the presence of a large hypocone upon 

 the last upper molar. The premolar-molar dentition is similar in 

 size and form to that of T. cultridens, but there are the following 

 important general differences: (1) Canines small and circular in 

 section; (2) a very short diastema, if any, behind the canine; 



(3) a large hypocone upon m'; (4) the infraorbital foramen 

 close beneath the anterior border of the molar [malar]. [Com- 

 parisons with T. cultridens follow.] 



Etymology. — StxXoos, double; Kcofos, cone; in allu- 

 sion to the presence of two internal cones on the third 

 upper molar. 



Present determination. — The species is valid; it is 

 now referred to the genus Rhadinorhinus. (See p. 431.) 



Telmatotherium cornutum Osborn, 1895 



Cf. Dolichorhinus hyogiiathus (Osborn), this monograph, page 409 



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

 7, p. 90, figs. 10, 11, 1895 (Osborn, 1895.98). 



Type locality and geologic horizon. — Northeastern 

 Utah; "Telmatotherium cornutum beds," Eohasileus- 

 Dolichorhinus zone (Uinta B 2). 



Holotype and paratypes. — Osborn writes: 



The type of this species is a fine skull (No. 1851) [Am. Mus.], 

 while several other well-preserved skulls from the same levels 

 give us all the cranial characters and the superior dentition 

 (Nos. 1850, 1847, 1848, 1852, 1837). [See fig. 110.] 



Figure 109. — Type (holotype) of Telmatotherium diploconum 



Superior and lateral views of skull. The nasals are broken off. Am, Mus. 1863. After Osborn, 1895. 

 One-fourth natural size. 



Characters. — Osborn writes: 



Incisors f . Premolar-molar series, 208 millimeters. A nar- 

 row diastema. Upper canines lanceolate. Long premaxillary 

 symphysis. A well-developed nasofrontal protuberance. Top 

 of cranium completely flattened. No sagittal crest. An 

 infraorbital process upon malar. 



This species is remarkable for its very long flat-topped cranium 

 and its incipient knoblike osseous horns borne chiefly upon the 

 nasals but partly upon the frontals. These horns project 

 laterally and rise slightly above the general surface, and are best 



