122 



J. PAUL VISSCHER. 



TABLE III. 



EXPERIMENTS ON INDIA INK. 



Table showing results obtained in feeding Dilcptus on India ink. In the 

 columns under the headings of 0-4, are indicated the number of individuals 

 which formed o, i, 2, 3, 4, or more vacuoles each, containing India ink, dur- 

 ing the twenty minutes of the experiment. Ink was ingested by more than 94 

 per cent., but less than 28 per cent, formed more than a single vacuole con- 

 taining ink. 



In the experiments on all the other inanimate substances men- 

 tioned earlier, results were obtained which are, in the main, in 

 harmony with those presented in Tables L, II., and III. All these 

 substances, with the possible exception of sand, were ingested by 

 a great majority of the individuals used in the tests. Experimenta- 

 tion with sand was very difficult owing to the fact that it settles 

 very quickly, and that it is also difficult to see. My notes on the 

 few experiments made record only thirty-two per cent, as having 

 fed on this substance. The results obtained in experiments with 

 chalk are almost identical with those obtained with glass. In the 

 experiments on starch there does not appear to have been as sharp 

 a decline between the number forming only one vacuole and those 

 forming three or four vacuoles each within the twenty minutes. 

 In other words, the power of discrimination does not seem to be 

 as well developed in regard to this substance as it is in regard to 

 the others. These experiments on inanimate substances thus show 

 quite clearly that Dileptus when hungry will ingest insoluble sub- 

 stances, but that usually only one vacuole is formed. 



