PLATE CXXVIII 



Type Skull of Menodus tbigonoceras 

 Plate prepared under the direction of Professor Cope. One-third natural size. (See p. 529, also PI. CLVII) 



Am. Mus. 6355, type. Horsetail Creek, northeastern Colorado, Chadron formation. Generic characters are displayed in the 

 top view as follows: The skull is elongate, the zygomatic swellings are moderate (in the lithograph these swellings are too 

 heavy and broad). The nasals are elongate and distally square. The horns are trihedral at the base, the tips pointed and 

 recurved; the horns are directed outward and upward; the connecting crest is developed in the plane of the posterior face of 

 the horns; the middle of the occiput is not extended behind the condyles. 



A study of the table of measurements (p. 523) indicates that the lower jaw of this skull would very probably have dimensions 

 slightly larger than those of the type jaw of M. proutii; it is quite possible that M. trigonoceras may prove to be specifically 

 identical with M. ■proutii and therefore a synonym. 



