258 CAMP-FIRES IN THE CANADIAN ROCKIES 



toughness suggests a cushion, for the protection of some- 

 thing from severe shock or strain. It lies directly over 

 the occiput and the first two cervical vertebrae, and is 

 built upon the ligamentum nuchi, which lies upon the 

 top of the neck, and forms the chief support of the head. 

 Its anterior end spreads fan-shaped over the lambdoidal 

 crest and the parietal bone, firmly grasping the rear upper 



NUCHAL HUMP OF OUR LARGEST Ovis CANADENSIS. 



surface of the skull. Of course the posterior end of this 

 mass vanishes on the upper surface of the neck. 



On young rams and ewes with small horns this 

 strange reinforcement is not found. Evidently it is devel- 

 oped as an extra means of support for the heavy horns 

 of old rams, and a provision against cerebro-spinal men- 

 ingitis from overstrain on the spinal cord. 



In the rutting season, and also shortly before it, two 



