D. S. GEOLOGICAL SURVEY 



MONOGRAPH 55 PLATE CIV 



TYPE SKULL OF DIPLOCLONUS BICORNUTUS 



ic-fifth natural size. (See p. 501.) Am. Mus. 1475, Quinn Draw, Big Badlands, S. Dak., Chadron formation. This skull is 

 referred to the genus Diploclonns from the presence of an accessory knob or hornlct on the antero'intemal face of the horn. 

 It differs from jDiploclonus amplus in the smaller size of the horns and in the lesser ^vidth of the zygomata (the narrowness 

 of the skull is emphasized by lateral crushing). The side view[(AO shows the chara(5leriilics of the menodontine group (deeply 

 concave skull top, long ^out nasals, grinding teeth w^ith sharp external cingula). The top view (A^) sugge^s that of Menodus. 

 This skull was at firil regarded as that of a female, but the ^out canines and zygomata do not support this view 



