1901.] Allen, Musk-Oxen of Arctic America and Greenland. 73 



the basal portion of the horn in the two species. In length and curvature of the 

 horns there is very little difference between the two forms. The apparent 

 difference in the length of the horns of the two skulls photographed is due to 

 the horns of the Bache Peninsula specimen being very much worn, as is com- 

 monly seen in the horns of old bull Bisons. 



In these illustrations the relative greater breadth of the base of the horns is 

 strikingly indicated in the side view, where, in O. moschatus, the anterior 

 extension of the base of the horn conceals the greater part of the left eye- 

 socket, while in the Bache Peninsula specimen it does not hide even its posterior 

 border. It will also be noted that the occipital portion of the skull is exposed, 

 in both views, in 0. wardi, and concealed in O. moschatus, by the expanded 

 posterior base of the horns. 



Figures 1-4 are from photographs, all made to the same scale. The two 

 skulls here shown are both old males, in prime of life, the teeth being not 

 greatly worn ; the two specimens are strictly comparable as to age, as shown by 

 the teeth and sutures of the skulls. 



MEASUREMENTS OF SKULLS OF MALES OF 

 Ovibos moschatus AND 0. wardi. 



1 A, and B, Camden Bay, Alaska. Both specimens are fully adult, but specimen B is a little 

 older and larger than specimen A, the teeth in the latter being practically unworn, while in B 

 the teeth are moderately worn. 



2 No. 16604 is from the Barren Grounds east of the Mackenzie River, an adult male with 

 the teeth moderately worn. The skull lacks the lower jaw. 



3 Nos. 15594, I 5.S93 an d 15596, from Bache Peninsula are all adult males, the teeth showing 

 full maturityj being moderately worn in two of them ; they are therefore strictly comparable 

 with the specimens from the Barren Grounds. 



