27 



spccimina; the cell-wall appearod as a very thin line without any 

 perceptible thickness (Fig. 6 — ^11). 



Herewith the description of the structure is finished. We have 

 stated that the green chlorophyll corpusdes of SpongiUa are round 

 or oval hodies^ 1.7 — 3.8 (j. in diameter.^ surrounded hij a cell-wall, 

 and consisting of prof.oplasm and a chloroplast ; while perhaps a 

 nucleus is present^ hut a pyrenoide is absent. They inclose oildro/js, 

 hut carhohydrates ivere never to he found within them. From 

 these data we may conclude that, very likely, these chlorophyll 

 corpuscles are vegetahle cells. 



The structure of the green chlorophyll corpuscles of Ephydatia 

 completely agrees with that of tlie corpuscles of Spongilla. So they 

 too are vegetahle cells. 



h. Phy siological proofs. 



1. The green chlorophyll corpuscles of Spongilla as well as those 

 of Ephydatia, isolated from the sponge tissues, can reniain normcd 

 and alive foi\ 6 months, and even longer. They were isolated and 

 cultivated in the way mentioned above on pag. 9 — 11. I am 

 not going to treat these cultures here, but I refer to the 

 extensive culture-tables (Table 4) at the end of this paper. 



We know that, on the contrary, chlorophyll corpuscles isolated 

 from plant-cells are not able to live on ; as for instance they 

 swell and are destroyed, when put into water (see Brandt (8), 

 HuGo DE Vries (63), Jost (33) Kny (34), etc). 



2. The isolated gre.en corpuscles of both sponge types multijdy 

 rather strongly in cultures, especially during the first 2 months; 

 but stages of division are also to be found in cultures of 6 

 months, even in those of 9 months (Table 4, 9, 10). I shall treat 

 these stages af ter war ds. 



3. Green chlorophyll corpuscles, as we know them from the 

 sponge tissues, (dso occur free in )iature — viz. in the waters 

 in which the sponges are living — so, not inclosed by other 

 organisms, but quite independant. I found their number changing 

 from at least 200 per litre in the beginning of March up to at 



