147 



to the results of Vosmaer and Pekelharing (p. 139 — 140). I have 

 been able to observe it several times in my living preparations, 

 regarding symbiotic algae as well as carmine. 



A description may follow here. Fig. 69 represents a flagellated 

 chamber with its normal surroundings of „intercellular" substance 

 and amoebocytes (the figure has been drawn true from nature). 

 The shuttle-shaped amoebocytes with the green algae continually 

 slide in various processions - - often directed oppositely (see 

 arrows) — past the chamber ; no canals are to be seen. The 

 flagella show the normal rapid spiral- or undulating-motion. In the 

 choanocytic layer a number of green symbiotic algae are lying 

 together at the base, in groups of 5 — 15; sometimes such a 

 group is to be found in a protrusion of this layer (Fig.: 1). There 

 all at once, in less than no time, the algae of that group are 

 lying outside the layer, free in the „intercellular" space, but 

 still on their original place (Fig. : 2). So the protrusion of the 

 choanocytes must have been withdrawn and must have „left 

 behind" the algae. At least in this way one should explain the 

 phenomenon, that has such an exceedingly rapid course. Next the 

 algae, which got free in this manner, are slowly spread all over 

 the „intercellular" substance (Fig.: 5), from where the amoebo- 

 cytes will be able to take them up at their desire. That, in fact, 

 the amoebocytes do so, will appear from a following observation. 



But first I will describe another flagellated chamber in a prepara- 

 tion, in carmine suspension. Situation almost as in the preceding 

 figure, though here canals are to be seen. Here is to be observed 

 very distinctly how the carmine is ejected into the parenchyma 

 (Fig. 70, I — III ; from nature) ; namely two small grains {a and b) 

 ejected one after the other from a protrusion of the choanocytic 

 layer. The figures speak for themselves; in I the original condi- 

 tion is given; in II the successive removals of grain a, after it 

 has been expelled, are indicated by 1 — 5; and in III the same 

 is given for grain b. Here the ejecting takes place into a very 

 plastic tilsue-bridge. 



Then a flagellated chamber overloaded with carmine in the 

 same preparation (Fig. 71, true from nature), while the carmine 



