SEXUAL DIFFERENCES. 



41 



tusks (see fig. 1) is doubtless abnormal, and is doubtless owing 

 to their unsymmetrical development and overlapping at tbe 

 points, whicli must have interfered to some extent witli their 

 use, and hence have preserved them from wearing. 



Fig. 1. Odobccnus rosmarus, 5 . 



In the National Museum at Washington a,ve also four skulls, 

 which, though unmarked as to sex, are unquestionably those of 



