.INTRODUCTION. 



the lower portion of it. But Joliet also contends that 

 the ova are generally, if not always, a product of the 

 endosarc; and in taking this position he runs counter 

 to the common opinion. Huxley, indeed, has described 

 both ova and spermatozoa as developed from the funi- 

 culus in Bugula avicularia; but the received view un- 

 doubtedly has been that the former are developed 

 normally from the endocyst, at various points of the 

 cell- wall, but usually towards the upper extremity of the 

 zooecium. They are so figured by various authors ; and 

 in this position I have myself observed them. On the 

 other hand, Joliet has seen the ova produced in the funi- 

 culus (i. e. in the endosarcal tissue) in a considerable 

 number of species, and has minutely described their posi- 

 tion and the course of their development*. He also 

 holds that in many at least of the cases reported by 

 authors, the ova which they describe as derived from the 

 endpcyst, are really the product of the endosarc. For 

 example, in Farrella repens the ovary was long since 

 distinctly figured by Van Benedenf on the upper part of 

 the cell-wall, and described as a growth out of its inner 

 layer. I have seen it in this position, presenting all the 

 appearance of a pouch fastened to the lining membrane 

 of the cell. On examining young zooccia of this species, 

 in which the bud was in course of development, Joliet has 

 found the mother cells even at this early stage surround- 

 ing the funiculus. As the growth of the polypide ad- 

 vanced, the cells on the upper portion of the funiculus 

 had multiplied to a great extent* and taken on a special 



* He has positively determined the production of ova in the funiculus of 

 seven species. 



t " Recherches sur {'organisation &t%Lagvncula,'' Mem. Arad. Roy. Brux. 

 vol. xviii. pi. i. fig. 1. A, I! 



