148 



from the chamber as centre begins to spread through the „inter- 

 cellular" substance by little streamlets moving to and fro. The 

 flagella are in rapid spiral- or undulating-motion. In the choano- 

 cytic layer the small carmine grains are united at the base into 

 conglomerates, just as we saw already for the algae; while also 

 outside the chamber in the tissue the conglomerates are more 

 numerous than the separate grains (Fig.). Already some amoebo- 

 cytes in the neighbourhood have taken up carmine. This must be 

 originating from the choanocytes and have been taken from the 

 „intercellular" substance, as there is nowhere any carmine to 

 be seen in the whole preparation, except in 6 flagellated cham- 

 bers with their nearest surrounding. Now, after the preparation 

 has been in pure water all night, the next morning the above 

 mentioned chambers are almost without carmine; but in the 

 surrounding there are many carmine conglomerates, sometimes 

 still free in the „intercellular" substance, most often however 

 situated within the amoebocytes with algae (and then by times 

 within a vacuole). 



The here described phenomena of taking up carmine or algae 

 within the choanocytic layer, followed by ejecting into the „in- 

 tercellular" plasmic substance and being taken up again by the 

 amoebocytes with green algae, have been studied by me several 

 times, although not in all their minor subdivisions; and this not 

 only by observing normally living preparations of sponge-tissue, 

 but also with the aid of ravel preparations. 



One might now ask what happens to the particles captured, 

 after they have got within the amoebocytes with symbiotic algae. 

 I shall postpone this question to the next chapter, to first answer 

 the last question of p. 142. 



Does the sponge dispose of still other means of capturing float- 

 ing particles from the water? I have been able to answer this 

 question affirmatively, again by observation of my normally living 

 microscopic preparations. The phenomenon, however, is very dif- 

 ficult to observe, as a number of favourable conditions must be 

 realized together — which only happens very seldom. It was not 



