492 Mr. A. W. Waters on a Structure in 



fig. 3, b 2, PI. X. fig. 2, c : subsequently these large cells 

 disappear, first part of the contents, then the nucleus, and a 

 number of small dark cells float about attached to very fine 

 plasma-threads, which at first looked like tails of spermatozoa, 

 but tliey are attached to several dark cells and it would 

 appear as if they ave plasma-threads with nuclei upon them. 

 These points will have to be worked up wiih fresh material 

 by younger eyes to whom high power work is less trying. 



Beside the interest in the structure and function there is 

 the question of its occurring in several Adeonellce, in fact in 

 most examined, and it will no doubt be a character of classi- 

 ficatory value. 



In Adeo7\ella the embryo is very large, often in an enlarged 

 zooecium, called a gonoecium *; on the other hand, Betepora 

 has well-developed ovicells with moderate-sized embryos, and 

 large oral glands, wliereas none have as yet been found in 

 the Adeonidse. Sections have been cut of Betepora atitarciica, 

 Waters; B. Couchii, Hincks; B. fn'gido,'W.; B. hijipo- 

 crepis, W. ; B. /lirsiita, Busk; R. lepjraUoides, W. ; B.pro- 

 ducta, B., without any of the bodies being found. 



In A. contorta, &c., these bodies occur in zooecia in which 

 a large number of the polypides are in full activity, and in 

 whicli there are many embryos and testes ; but 1 have not 

 found them in zoaria, where almost every zooecium contains 

 a polypide, so that it may be that they only occur where 

 vitality is diminishing and they may remain when nearly all 

 the polypides have died down. As this probably is a 

 character of the Adeonida^, a consideration of the family is 



* Gonoecium was used by Ilincks for a modified zocecium set aside 

 for reproductive functions, and in speaking of the gonoecium of Adeouidse 

 it has been considered that the cells for the enibrvo were all larger. 

 1'his is by no means the case, as I have seen in a considerable number of 

 species, though in perhaps tlie majority it may be larger. I may mention 

 as exam])les Adcona foliacen. var. fascia/is, Kirchenpauer, which has the 

 embryo in a large sac near the distal end, and is about half the length of 

 a zocecium and occurs in all parts of the zonrium ; Adeonelio/isis <Ii6to7}ia, 

 B., in which, after examination of a considerable number, I have found 

 no zoopcia specially larger than the others, but here, again, the embrvo is 

 in a large sac at the distal end; Adeone//a contorta. yi., in v,]uc]i the 

 embryo is veiy large, about the length of a zooecium ; Adeonella poly- 

 sconiella, Rss. (as redescribed by Manzoni), has nil the zocecia of equal 

 size with the embryo in a thick-valled sac near the distal end of the 

 zi oecium and rather less than half the length of a zocecium. 



Nor must we imagine that an enlarj;ed zoo'cium is necessarily only for 

 a large embryo, as there will be a polypide in it, or it may be almost 

 tilled with testes ; in fact the series of cliarges in coutei.ts may be some- 

 what similar to those known in the ordinary zocecia. 



As previously explained, I shall continue to use ovicell as a general 

 term, and then Ave can say the ovicell is a " gonoecium. " &c. ic. 



