176 SEA-SIDE STUDIES. 



hypotlietically. As it is, I propound a suggestion, 

 which the researches of some more fortunate inquirer 

 may confirm, or rectify. First, be it remembered that 

 the ova and spermatozoa are developed in precisely 

 the same portion of the lining membrane on the free 

 border of the septum. This is the statement of Kolliker 

 and HoUard, who further remark that it is only by the 

 difference of colour that the testis is distinguished 

 from the ovary. If these anatomists found ova in one 

 animal, and spermatozoa in another, whereas I found 

 both in one and the same animal, four possible explan- 

 ations suggest themselves : 



1st. There are Actiniae in whom the ova and sperma- 

 tozoa are intermingled ; that is to say, one grape-like 

 cluster will contain both kinds of cells. 



2d. There may be others in whom the spermatozoa 

 accumulate on one part of the septum, and the ova on 

 another part of the same septum ; or different septa 

 may bear different kinds of cells. 



3d. There may be others — and this has its parallel 

 in other Polypes, in Crustacea, and in Insects — which 

 produce nothing hut ova ; and these ova may develop 

 into embryos, without the concom^se of spermatozoa 

 at all. 



4th. Or finally, the slight indication of the sejDara- 

 tion of sex, which is presented when one side of the 

 septum, or one of the septa, develops only one kind of 

 cell, may be further carried out in some species, and in 

 them the complete separation of sexes takes place. 



Of these four possible forms, I have positive obser- 



