111 



selves witli the general fornmlatinfj- of the answer given on p. 109. 



The final result of our research info the use of the y^sijmhiotic''' 

 associatmi (of sponge and yreen ah/a) f o the sponge is therefore: 



It is either the want of food of the sponge — which might he 

 stronglg increased in darkness — or {and) the y^poisonous'''' influence 

 of harmful products of metabolisin of the sponge (fo he considered 

 as a reactioti of defence agaijist a foreign intruder) which 

 continuaUij destroys green symhiotic algae in the amoehocytes ; 

 atid exactly those algae, the power of resistance of which is already 

 'tveakened for some or other reason — for instance by having heen 

 in darkness — (p. 102 — 109). All algae killed in this way come 

 to the henefit of the nourishment of the sponge ; as this one digests 

 and dissolves them entirely either free in the protoplasm of its 

 amoehocytes or in food vacuoles, keeps the products of the decom~ 

 position (p. 96 — 97) and rehuilds its own cell parts ivith them,, 

 naniely for instance the oildroplets and carhohydrate glohules 

 (p. 98 — 102). These oildroplets and carhohydrate glohules in their 

 turn are, among others, the source of the great quantity of energy, 

 which the sponge transforms in the fagellar mofion of its choano- 

 cytes (p. 100). 



For the present no decision can he given ahout the exact signi- 

 ficance for the life of the sponge of the O.,, which the living green 

 algae in light secrete within its tissues (p. 93). It may he, that this 

 O., is of much significance ; even so much, that the katahoUc phase 

 of the process of metaholism in a green sponge in light has quite 

 another course hy it — namely gives a relatively much larger 

 quantity of energy to the sponge — than in the sponge in darkness 

 {p. 98, 103, 109 — 110). Some indications were found for this; hut 

 this important question requires quite a seperate research, before 

 anything can he said for certain. 



As we saw {p. 96, 87, 92) it is very likely, that direct transfer 

 of products of photosynthesis from the living green algae into 

 the sponge tissue does not take place at all. 



When next we ask, whaf in fact the „symhiotic''' relation of 



