PLATE CXC 



Skulls of Female Brontotherium 

 (See pp. 571, 576, also PI. CXCII) 



A, Female skull referred to Brontotherium? gigas? (Am. Mus. 1006), Big Badlands, S. Dak., Chadron formation. One-fifth natural 

 size. This specimen was referred to the genus and species B. gigas on account of the similarity of the basal section of the 

 horns, but the characters of the canines and premolars suggest reference to Brontops cf. B. robustus. 



fii, B^, Female skuU referred to Brontotherium curtum (Am. Mus. 1005), Big Badlands, S. Dak., Chadron formation. One-fifth 

 natural size. This specimen is undoubtedly a brontothere, as shown especially by its premolars. The short horns are very 

 massive at the base, and the connecting crest is high. Somewhat similar horns were described by Cope under the name 

 Menodus peltoceras. (See p. 229.) 



