370 



SCOTT. 



EXPLANATION OF PLATE XX. 



Restoration of Protoceras celer, one- third natural size. The skull is taken 

 from Osborn and Wortman's figure of the male, drawn to the proportionate 

 length of the female skull which belongs to the skeleton. The secondary sexual 

 characters being principally confined to the head, there is nothing misleading 

 in this association of the sexes in one figure, especially in one of such small scale. 

 The remainder of the skeleton belongs to a single individual, with the exception 

 of the humerus, atlas, 12th thoracic and ist caudal vertebrae, which are supplied 

 from other specimens. 



