88 



tion (which is not at all under the control of the sponge). Besides, 

 what might be the reason for that larger consumption? Perhaps 

 this reminds of the fact mentioned on p. 53, that green Spon- 

 gillae in light often prove to grow much quicker than colourless 

 ones in darkness. But growth is always only a consequence 

 of, among others, the quantity of food disposable; in other 

 words : if really the lesser growth of the colourless sponges were 

 the consequence of the smaller quantity of oildroplets they can 

 dispose of, it would be a very singular fact that there is still 

 rather a large number of those oildroplets left in the amoebocytes 

 of such a colourless sponge, that there is even more left than in 

 a green sponge in light! Besides, an organism especially wants 

 protein to grow and not so much fat (or carbohydrates). Last not 

 least, I have to propose another question, much more important, 

 in case one sticks to the opinion, that the oildroplets really get 

 directly from the green algae into the amoebocytes ; this question 

 namely, how — if this supposition were right — the very few 

 green algae, which are present in a colourless sponge in darkness 

 (or twilight), could possibly procure all those oildroplets, which 

 we find in the amoebocytes of that sponge; while, moreover, 

 those algae can hardly photosynthesise there, even will have to 

 die very soon (p. 70). Consequently these few green algae almost 

 exclusively dispose of the oildroplets, which they already carried 

 when imported from the outside to within the sponge, and 

 which in dark they are certainly not going to give immediately 

 to its tissues! As we are thus obliged to find for the colourless 

 sponge another explanation for the presence of oildroplets in the 

 amoebocytes, the suggestion is very likely, that this (other) ex- 

 planation will also prove to go for the green sponge. Besides, 

 the whole supposition of oildroplets being ejected by the green 

 algae by itself sounds rather unlikely, as I stated already above 

 under point 4. 



But lateron I will mention quite another, much more logical 

 way, in which the amoebocytes do get really their oildroplets 

 from the algae (p. 98 — ^99). 



All that is stated sub 5 about ejecting oildroplets by the green 



