SKULL OF C!«RYS()CHLORIS. 459 



Addendum (July 12, 1916).— After my paper had been com- 

 municated to the Society, Mr. D. M. S. Watson called my 

 attention to the fact that there is generally present in the 

 Common Seal [PJioca vitulina) a bone which also appears to be a 

 tabular. It has, of course, long been known that not infrequently 

 a distinct bone occurs in the corresponding region in the human 

 subject ; and we may, I think, conclude that though most 

 mammals have lost the tabular there is a tendency for it to re- 

 appear hj reversion in forms in which, owing to the configuration 

 of the brain, the occiput is largely developed. — R. B. 



