PLATE CLXXXIX 



Skull of Brontotherium platyceras 



One-fifth natural size. (See p. 579, also PI. CLXXXVIII) 



Skull referred to Brontotherium platyceras (Am. Mus. 144S), Cheyenne River Badlands, S. Dak., Chadron formation, probably 

 from the upper part of the Titanotherium zone. This side view shows the extreme length of the horns and height of the con- 

 necting crest in this brontothere. Vertical crushing has pitched the horns forward, so that the nasals are now far in advance 

 of the skuU. The zygomata also are displaced forward. The jaw (Am. Mus. 1061) does not belong with the skull. The 

 relationship of this animal to B. platyceras and B. curtum is discussed above. (See PL CLXXXVIII.) 



