U. S. GEOLOGICAL SURVEY 



MONOGRAPH 55 PLATE CLXXVII 



SKULL OF BRONTOTHERIUM CURTUM 



Plate prepared under the dirediion of Professor Marsh. One-fourth natural sise. (See p. 575.) SkuU q (Nat. Mus. 4946), Big Bad- 

 lands, S. Dak. (TIndian Dra-w^), Chadron formation, level upper C (Hatcher). This skull is somewhat more progressive than the ■ 

 type of B. medium, with broader zygomatic arches, flatter horns, and more abbreviated nasals. The dental series is a little smaller. 

 The right horn has been broken off and healed during life (See PI. CLXXXV^^B) 



