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until I had obtained in another way the proofs, that there should 

 still exist in the sponge an entirely different method of capturing 

 food, that I succeeded in observing it in my living preparations. 

 Those proofs were in short: 



1. If one makes a ravel preparation of a little sponge (Spon- 

 gilla or Ephydatia) that has been in a suspension of carmine or 

 symbiotic algae for some hours — and thereby has become light- 

 red or light-green — , then under the microscope the carmine or 

 the algae prove to be present: 



a. in a great quantity of course in the choanocytes of the fla- 

 gellated chambers. 



h, little or not yet in the amoebocytes with symbiotic algae — 

 for the transport from the choanocytes to these amoebocytes 

 takes time. 



c. in a relatively great quantity in a not very numerous kind 

 of amoeboid cells, which distinguish themselves from the 

 ordinary amoebocytes with symbiotic algae by their gene- 

 rally almost entire lack of such algae, while sometimes 

 they hold all sorts of detritus (by times situated in vacuole). 

 Their nucleus is, as that of the amoebocytes, vesicular. 



2. While now in the choanocytes the carmine generally occurs 

 as small grains or as conglomerates of small grains, it appears 

 to be present in the cells, mentioned under c, principally in big 

 grains or their conglomerates. (Perhaps one will doubt, if car- 

 mine grains and conglomerates are so easy to be distinguished. 

 In fact this is the case: the grains are generally simple in out- 

 line, straight and angular, as pieces of a crystal, and internally 

 homogeneous, refractive red ; while the conglomerates are appa- 

 rently more rounded off, but in reality more irregular by num- 

 bers of re-entering angles, and internally not homogeneous but 

 red, everywhere interrupted by black ; which is conceivable by 

 their structure.) 



3. Very often one can clearly see in a normally living mi- 

 croscopic preparation, which has been in carmine suspension for 

 some hours already, that the carmine, except in the choanocytic 

 layer of the flagellated chambers, is also to be found in mass in 



