366 F. W. GAMBLE AND FREDERICK KEEBLE. 



working- with material sent to Gratz from Roscoff, has 

 described the g'eotropic and phototropic reactions of 

 Couvoliita, and has figured and carefully described the 

 histological peculiarities of the green cells. Georgevitch 

 (1899)^ in the course of a research on the embryology of 

 Convoluta, has experimented on its development. Geddes, 

 von Graff, Haberlandt, and Georgevitch are agreed that 

 Convoluta does not ingest solid food, but depends for 

 its food on the carbohydrate and proteid-synthesising pro- 

 cesses of the green cells. In support of this view, Geddes 

 (1879 b) points to his observation that Convoluta dies 

 quickly — within three days — when kept in the dark ; von 

 Graff (1891) to his failure to discover any traces of food 

 in Convoluta, and to the paucity of wandering cells; 

 Georgevitch (1899) to the mortality which he notes among 

 just hatched animals when secured, as he supposes, from 

 infection by being placed in filtered water. 



In the present paper we bring forward new facts which 

 show that this view — that Convoluta is obligately parasitic 

 on its green cells — is not well founded; we prove that the 

 above-mentioned observations on which this view is based are 

 erroneous, and offer a somewhat different view of the relations 

 which obtain between Convoluta and its green cells. 



The origin of the green cells has been the subject of 

 speculation on the part of Haberlandt and Georgevitch. 

 Haberlandt considers the alternative possibilities of external 

 or internal origin. He inclines to the view that, whatever 

 the primitive origin of the green cells may have been, they 

 have been so domesticated to the service of Convoluta as to 

 have lost the power of independent existence, and to have 

 come now to be transmitted in the ogg, perhaps in some 

 way like that in which the chloroplast of a green plant is 

 transmitted in the egg as a colourless plastid. Georgevitch, 

 relying on the negative results of his experiments, concludes 

 that young colourless Convolutas become green by infection 

 from the sea water. 



By culture experinu>nts, and by observations on young and 



