their protoplasin. Now, as I have been able to observe in my 

 living preparations quite another waj of movement of the flagella 

 and the water-current as being the normal one in the flagellated 

 chambers, the way in which the choanocytcs capture their food 

 was also bound to prove wholly different. The food-particles are 

 by no nieans captured within, but at the outside of the collars 

 or at the outside of the colhir-cells themselves; so exactly in the 

 same way as in the Choanotiagollata (cf. Doflein (17)). Already 

 JoKDAN (32) said: „Den Vorgang der „Phagocytose" durch die 

 Kragenzellcn mit demj enigen zu analogisieren, den wir bei den 

 Choanoflagellaten kennen lernten, ist sehr verlockend, aber das 

 vorliegende Beobachtungsmaterial reicht nicht hin, uns ein Recht 

 zu solchem Analogisieren zu geben". Cotte (12) 1902, namely, 

 seemed to have observed something as a capturing of food at 

 the outside of the collars, although he said the capturing within 

 the collars to be the chief manner of ingestion. 



Quite separate from the problem of ingestion of solid food re- 

 mains Pütter's theory (48, 49) 1909, 1914, which says that 

 sponges do not feed so much with micro-organisms as with or- 

 ganic substances in solution, present in the water. 



(See Summary, point 21 — 23). 



7. Finally the problem of defecation and excretion ; up to now 

 it has been studied but little, and the few results we possess, 

 and which we owe amongst others to Masterman (42) 1894 and 

 Cotte (13) 1903, are only accepted in literature with reserve — 

 BuRiAN (10) 1910, JoRDAN (32) 1913 — . There are mentioned, 

 for instance, an expulsion of cells loaded with waste solids at 

 arbitrary points of the inner or outer surface of the sponge-body, 

 and a process of defecation by the choanocytes. Now, I have 

 been able to observe in my living preparations, that defecation 

 (and probably excretion at the same time) takes place on a large 

 scale by means of vacuoles. And that probably this process should 

 be considered partly in direct relation to the above (point 6) 

 mentioned second way of capturing (larger) particles. So we get 

 to know a — very necessary — quickly working system of 

 cleansing of the sponge (see Summary, point 24 — 25). 



