PLATE CXLVIII 

 Skulls of Megacerops acer 

 Top view. One-fourth natural size. (See p. 545, also PI. CXLVI) 



A, Referred female skull (Am. Mus. 6350; type of Symborodon altirostris Cope), Horsetail Creek, northeastern Colorado, Chadron 



formation. (Compare with supposed M. bucco female, PL CLVI.) 



B, Type (Am. Mus. 6348), Horsetail Creek, northeastern Colorado, Chadron formation. The top of the skull is long and com- 



paratively narrow, as in males of Brontotherium. 



