162 



BULLETIN OF THE 



The accompanying figures show the four t5^es of skull as seen in the fronto- 

 nasal region. The first type, with long nasals and short erect horns, is repre- 

 sented by M. coloradensia and characterizes also M. ingens and M. angustigenis. 

 The second type, with medium nasals and short obliquely placed horns, is 



