DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



221 



longer and more widely divergent at the base. The angle of 

 inclination of the horns and the diminutive proportions of the 

 nasals, as well as the form of the top of the cranium, all bring 

 this specimen near S. acer and separate it from other known 

 species. Unlike S. acer, the horns are not united by a ridge. 

 [This is an error.] The specimen is incomplete in the supra- 

 occipital region, the zygomatic arch is fragmentary, and the 

 maxillary, palatine, and basioccipital regions are much dis- 

 torted. 



Menodus platyceras Scott and Osborn, 1887 

 Cf. Brontotherium platyceras, this monograph, page 578 

 Original reference. — Mus. Comp. Zoology Bull., vol. 

 13, No. 5, pp. 160, 161, fig. 4, 1887 (Scott and Osborn, 

 1887.1). 



Subsequent reference. — The cranial evolution of Tita- 

 notherium, p. 186, fig. 7A, 1896 (Osborn, 1896.110). 

 The specimen figured is not the type. 



Figure 177. — Anterior part of skulls of (1) " Megacerops colorodensis" (not the type), now referred to Allops 

 marshi; (2) Menodus tichoceras (type) (present determination, Brontotherium tichoceras) ; and (3) Menodus 

 dolichoceras (type) (present determination, Brontotherium dolichoceras) 



Specimens in the Museum of Comparative Zoology, Harvard University. After Scott and Osborn, 1887. Greatly reduced in size. A, Side 

 views: B, front views, showing the variations in the horns, nasals, and anterior nares; O, top views, showing the nasals and horns, and sections 

 of the bases of the horns. 



Revised measurements 



IVIilUmeters 



Occipital condyles to nasal tips 690 



Free length of nasals 46 



Free breadth of nasals 90 



Outside measurement of horns 310 



Anteroposterior diameter of horns 85 



Transverse diameter of horns 125 



Etymology. — 56\ixoi, long; Kepas, horn. 



Present determination. — As shown in Chapter VI 

 the present species probably pertains to Brontotherium 

 rather than to Symhorodon. 



Type locality and geologic horizon. — Big Badlands, 

 South Dakota; Chadron forma'tion (Titanotherium 

 zone, Chadron C); exact locality and level not re- 

 corded. S. Garman, collector. 



Type. — A pair of horns with the nasal bones at- 

 tached. Now in the Museum of Comparative Zoology 

 at Cambridge, Mass. (See fig. 178.) 



Neotype.SknW (Am. Mus. 1448). 



Characters. — Scott and Osborn write: 



Nasal bones e.xtremely short and obtuse, as in M. dolicho- 

 ceras and M. acer. The inner [posterior] contour of the horns 



