1877.] Mr Balfour, On the development of the Vertebrate Ovum. 75 



October 22, 1877. 

 Prof. Clerk Maxwell, F.R.S., President, in the chair, 



A communication was made to the Society by 



Mr Balfour, On the Development of the Vertebrate Ovum. 



The points dealt with in this paper were (1) the nature of the 

 stroma of the ovary, and (2) the relation of the permanent ova to 

 the large cells of the germinal epithelium, named primitive ova by 

 Waldeyer. 



With reference to the first point the author shewed the stroma 

 of the ovarian part of germinal ridge to be in Elasmobranchs 

 a derivative of the germinal epithelium, and not, as has usually 

 been supposed, of the snbjacent mesoblast, and pointed out the bear- 

 ings of his conclusions on the controversies which have arisen as to 

 the nature of the follicular epithelium. 



In dealing with the second point he stated that the permanent 

 ova were not direct derivates from the primitive ova, but that 

 by a rapid division of the nuclei of the latter polynuclear masses 

 were formed, comparable with the egg-tubes of many Inverte- 

 brata. From these masses the permanent ova took their rise 

 by the same series of steps as in the egg-tubes of the Inverte- 

 brata. 



October 29, 1877. 

 Prof. Babington, Vice-President, in the chair. 



A communication was made to the Society by 



Prof. LiVEiNG, On the metamorphism of the rocks of the 

 Channel Islands. 



In the Autumn of 1876 I spent three days in Guernsey in 

 company with Mr Osmond Fisher, and was mucli struck by the 

 variation in the amount of metamorphism which the rocks there 

 appeared to have undergone. I have this summer again visited 

 the island, and have also visited the other islands of the group, 

 but my remarks relate principally to Guernsey. 



(J— 2 



