220 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Characters (abbreviated from Scott and Osborn). 

 Dentition: I 2, C 1, P 4, M 3. The skull is described 

 as 29 inches [736 mm.] in length; with a narrow and 

 elevated anterior portion; nasals of medium length, 

 with short, obliquely placed horns, zygomatic arch 

 very massive, presenting a bulge in the posterior half 

 which is much less prominent than in S. iucco. 



Etymology. — relxos, wall; Kipas, horn; possibly in allu- 

 sion to the high connecting crest. 



Type locality and geologic horizon. — South Dakota; 

 Chadron formation {TitanotJierium zone); exact local- 

 ity and level not recorded. 



Type. — A skull incomplete in the supraoccipital 

 region; zygomatic arch fragmentary; maxillary, pala- 

 tine, and basioccipital regions much distorted. Now 

 in the Museum of Comparative Zoology, Harvard 

 University. (See fig. 177.) 



Characters. — Scott and Osborn write: 



Figure 176. — Cope's cotypes of Menodus angustigenis 



A, Right maxilla (subsequently made the type of Haplacodon angustigenis), three-sixteenths natural size; B, left halt of a lower jaw (now referred to Menodus 

 sp.) , three-sixteenths natural size; C, symphysis mandibulae (leetotype), one-third natural size (Ci, front; Ci, right side; C3, under side). 



Present determination. — This species is provisionally 

 referred to Brontotherium, but its exact position in 

 that phylum is uncertain. (See p. 565.) 



Menodus dolichoceras Scott and Osborn, 1887 

 Cf. Brontotherium dolichoceras, this monograph, page 572 



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

 13, No. 5, p. 160, figs. 3, 3; 5, 3; 6, 3, 1887 (Scott and 

 Osborn, 1887.1). 



Dentition: I ?, C^-, P^, M^. Upper premolars with a faint 

 internal cingulum. Nasal bones extremely short and obtuse. 

 Horns extremely long and powerful, directed obliquely forward 

 and outward, projecting beyond the nasals in side view. The 

 section is suboval at the base, with the long axis obliquely 

 transverse. Cranium very broad and saddle-shaped above 

 the orbits, narrowing somewhat posteriorly. A prominent and 

 overhanging superciliary ridge. Postglenoid and post-tym- 

 panic processes united for a short distance. The skull which 

 we have made the type of this species is much larger and more 

 powerful than Professor Cope's type of jS. acer. The horns are 



