27 



specimina; the cell-wall appeared 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 corpuscles of Spongllla are round 

 or oval bodies^ 1.7 — 3.8 [/, in diameter., surroimded by a cell-wall^ 

 and consisting of protoplcism and a chloroplast; while perhaps a 

 nucleus is present., but a pyrenoide is absent. They i?iclose oildrops., 

 hut carbohydrates were tiever to be found within them. From 

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

 corpuscles are vegetable cells. 



The structure of the green chlorophyll corpuscles of Ephydatia 

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

 too are vegetable cells. 



b. Physiological proofs. 



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

 of Ephydatia, isolated from the sponge tissues, can remain normal 

 and alive for 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 Yries (63), Jost (33) Kny (34), etc.). 



2. The isolated green corpuscles of both sponge types multiply 

 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 afterwards. 



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

 sponge tissues, also occur free in nature — 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 



