1073 



considerable distances (e. j?. one quarter of the outer over surface 

 of a flagellated chamber) (fig. 4). Thus it is seen, for instance, that 

 by this current carmine-particles are carried off aside of the flagellated 



Fig. 4. Semi-diagrammatic representation of a flagellated chamber with 

 the layer of circulating protoplasm (pl.l.) lying against the base 

 of the choanocytes on the side of the incurrent canal. The 

 choanocytes-layer (ch.l.) is drawn as one whole. It lodges 

 numerous captured carmine-particles. Similar particles are carried 

 along in the protoplasm-layer (1—2 — 3) to a deposit place, 

 from which now and then a large (fecal) conglomerate is 

 extruded. (Magnification about 1000 times). 



chamber into the parenchyma (fig. 4). It is evident that this layer of 

 streaming plasma leaves the prosopyles uncovered. Now, if there comes 

 with the water-cunent through the incurrent canal a particle that is 

 too large to pass a prosopyle, and therefore remains sticking in it, 

 nothing is seen to happen in the first 10 minutes; but then a movement 

 arises and the particle is, outside along the flagellated chamber — 

 therefore between choanocytes and incurrent canal — , very slowly 

 carried off aside into the parenchyma. So this is brought about by the 

 above-mentioned layer of streaming plasma, so that the prosopyle 

 again become accessible (fig. 5). It needs no proof that, if possible, 

 the particles taken up in this way will also serve as food to the 

 sponge. 



In any case, therefore, the fresh-water sponge has 2 different 

 methods of taking-up food (possibly even more). Which method is 

 most utilised, will depend, in my opinion, on the size of the particles 

 of food present; seeing, that the ingestion hy the collar cells is used 

 especially for smaller particles and that by the plasmic layer for 

 larger ones. 



