Physiology. — "A contribution to the phi/dology of the fresh- 

 water sponges {Spongillidaey . Hy H. van Trigt. (Communi- 

 cated by Prof. C. A. Pekelharing). 



(Communicated in the meeting of November 24, 1917). 



In this paper I propose to give a short preliminary account of 

 the results obtained in the course of an investigation, covering 

 many years, into the chlorophyll, the movement of water (in the 

 canal system) the ingestion of food, and the defecation and excretion 

 in the fresh-water sponges. A detailed account of this investigation will 

 shortly appear in the Tijdschrift der Nederl. Dierkundige Vereeniging. 

 The work was carried out in the Zoötomic Laboratory at Leyden 

 during the lifetime of Pi'ofessor Vosmaer, and is in part a continu- 

 ation of his well known treatises "On the ingestion of food by 

 sponges" and "Observations on Sponges" published in collaboration 

 with Professor Pekelharing in 1898 in the Verhandelingen of 

 this Academy. 



A. The Chlorophyll. 



I. In 1882 — 1883 there arose polemics between Ray Lankester ^) 

 and Brandt ") on the question whether the chlorophyll, that is found 

 in the amoebocytes of fresh-water sponges in the form of oval 

 corpuscles 2 — 3 n large, was of animal origin, so chlorophyll 

 formed by the sponge itself as an inherent part of its cells, or 

 whether it belonged to unicellular algae which would be associated 

 to the sponge in symbiosis. Lankester held the first opinion, Brandt 

 the second. Brandt's arguments were rather strong, but not so 

 conclusive as to enable him to convince Lankester. Nevertheless 

 Jater-on Brandt's conclusion is almost generally acknowledged to 

 be exact in literature, although in English handbooks Lankester's 

 view is still maintained, as for instance by Sollas in the Cam- 

 bridge Natural History (1906). 



^) Quart. Journal of Microsc. Science, 1882. 

 2) Arch, fur Anat. u. Physiol., Physiol. Abth., 1882. 

 Mitth. a. d. Zoolog. Station zu Neapel, IV, 1883. 



