U. S. GEOLOGICAL SURVEY 



MONOGRAPH 55 PLATE CLXVII 



Ai 



TYPE SKULL OF BRONTOTHERIUM HATCHERI 



One-fifth natural size. (Sec p. 563.) Skull a, type (Nat. Mus. 1216), Big Badlands, S. Dak. C?Ck>rral Draw), Titano' 

 therium zone, level upper B (Hatcher). Ai, Palatal view. The grinding teeth conform to the Brontotherium 

 pattern, ^vhich, apart from size, appears to show little variation in the diflferent species. A3, Front view of 

 horns. The horns in this animal are considerably shorter than those of the typical B. gigas (which is recorded 

 from a higher level), and they are also less flattened, especially at the base; the connecfting creft is low^ 



