308 F. W. GAIMBLE AND FRRDERTC'K KEEBLF. 



Section II. — The Food of Convoluta. 

 1. Previous Observations. 



Whereas diatoms, rotifers, and other solid ingesta are 

 constantly found in allied Turbellaria, previous observers 

 have failed to demonstrate the presence of '^ food " in the 

 bodies of Convoluta roscof fensis. 



Geddes (1870) kept Convoluta alive for four to five 

 weeks without food. Haberlaudt (1891, p. 88) did not find 

 a single specimen containing food taken up from withont, 

 although he kept Convoluta in a well-stocked aquarium at 

 Gratz. Von Graff (1891, p. 70) states that of all the living 

 and sectioned Convoluta he examined, only cue or two 

 contained, any foreign bodies, and these foreign bodies were 

 without exception discharged month-pieces of the " bursa," 

 The pancity of phagocytes in the body of Con vol uta, and 

 the supposed barren natnre of the sand, also led von Graff 

 to conclude that this animal did not live on animal food. 

 Georgevitch (1899), after examining larval, adolescent, and 

 adult Convoluta, states (p. 358) that 'Mt is certain that 

 Convoluta does not take nonrishment (i. e. from without) 

 either in the embryonic or adnlt stages. '^ 



These authors agree that Convoluta is nourished by 

 means of the green cells which form an assimilating tissue in 

 the superficial parenchyma. Geddes (1879) has shown that 

 these green cells produce starch, and inasmuch as he found 

 that Convoluta dies rapidly when placed in the dark, but 

 lives for weeks in the light, he concluded that Convoluta 

 lived upon the starch of the green cells. Ilaberlandt (1890) 

 offered a more elaborate explanation of the mode of nutrition. 

 Failing to find any trace of digestion of the green cells as a 

 whole by the animal tissue, and observing the fragmentation 

 of these green cells when Convoluta Avas fiimly pressed 

 between slide and cover-slip, Haberlaudt inferred that Con- 

 voluta fed by digesting such fragments, by digesting starch 



