143 



It goes without saying, after the results obtained by Yosmaer 

 and Pekelharing with carmine-feeding to Spongillae, that I too 

 found the ^>'s^ ^-ï/es^/ow affirmatively answered : The particles fïoatmg 

 in the water are captured in a mass hij the choatioci/tes of the 

 flagellated chambers; very often their layer is dyed quite red by 

 it (in case of carmine nutrition). It also stands to reason that, 

 since I had stated a mode of motion of the flagella and the water 

 within the flagellated chambers quite different from that described 

 by both the investigators mentioned, also the ivaij in which the 

 choanocytes capture the food particles was bound to prove wholly 

 different: those particles are not captured inside the collars at all, 

 as Yosmaer and Pekelharing thought, but on the contrary out- 

 side-between the collars (especially at their base) or between the 

 bodies of the choanocytes themselves. That this must necessarily 

 be the case, immediately appears from Fig. 55, 59 and from Fig. 63, 

 the diagrammatic representation of the water current in a flagel- 

 lated chamber as the resultant of the streamlets produced by 

 each flagellum separately. For the bodies and collars of the choano- 

 cytes must, so to say, filter the water, circulating between them, 

 free from floating particles. 



I shall now give a description of the capturing of carmine, as 

 I have been able to observe so many times in my living sponge 

 preparations. So the little sponge is in carmine suspension under 

 oil immersion in an Engelmann case; one has selected a favourably 

 situated flagellated chamber. 



It is beautifully to be seen how the carmine is captured! Con- 

 tinually grains run on rather rapidly to the flagellated chamber, 

 carried along by the water in the incurrent canal; they slip into 

 the prosopyle, but tlien they are either immediately kept or first 

 they move quickly a little aside into the choanocytic layer, and 

 stick there. On more accurate observation, however, the grains, 

 after entering the prosopyles, prove in most cases to slip through 

 the choanocytic layer, but, when having got to the base of the 

 collars, to suddenly deviate aside and to be soon captured — still 

 at the bases of tlie collars. Only very seldom a grain penetrates 

 any farther, in the zone of the collars themselves ; as most of 



