U. S. GEOLOGICAL SURVET 



MONOGRAPH 55 PLATE CVIII 



TYPE SKULLS OF DIPLOCJLONUS AMPLUS AND D. TYLERI 



One-sixth natural siie. (See pp. 503, 504, also Pis. CVI and CIX.) A, Diploclorvus amplus, type (Yale Mus. l^Ol'^)' 

 South Dakota, Chadron formation. Figure prepared under the direaion of Professor Marsh. This view exhibits 

 well the pronounced brachycephaly, the flattening of the horns, the prominent hornlets, and the abbreviation 

 of the nasals. (See PI. CVII.) B, D. tyleri, type (Amherft College Zool. Coll. 327), near the head of Bear Creek, a 

 tributary of Cheyenne River, S. Dak., Chadron formation. (After R. S. Lull.) In the top view this skull 

 approaches D. amplus 



