U. S. GEOLOGICAL SURVEY 



MONOGRAPH 55 PLATE CXXIX 



TYPE SKULL OF MENODUS TRIGONOCERAS 



Am. Mus. 6355, Horsetail Cree 

 This viewT shows the i 



:, northea^ei 

 scored parts i 



1 Colorado, Chadron formation. One-fourth 



I outline. (Compare Mewodus giganteus, PI. CXL) 



