FEEDING REACTIONS IN DILEPTUS GIGAS. 



123 



B. Animate Substances. 



In comparison with the results obtained in the above-described 

 experiments on inanimate substances, those obtained in experiments 

 on living material stand out in sharp contrast. Experiments were 



TABLE IV. 



EXPERIMENTS ON Euglena. 



Table showing results of ten experiments obtained in feeding Dileptus on 

 Euglena. In the five columns under the headings 0-4, are indicated the num- 

 ber of individuals which formed, in twenty minutes, o, i, 2, 3, 4, or more 

 vacuoles containing Euglena. Euglena was ingested by more than 94 per cent, 

 and a second vacuole containing this flagellate was formed by 89.3 per cent, 

 of the individuals tested. 



made with most of the forms listed in Table VII. The results 

 obtained with all of these forms are essentially the same. Those 

 obtained with Euglena, Colpidiuni, and Chilomonas are presented 

 in Tables IV., V., and VI. By referring to these tables it will be 

 seen that Euglena was ingested by 95 per cent, of the dilepti tested, 

 89 per cent, forming three or more vacuoles. and 50 per cent, four 

 or more ; that Chilomonas was ingested by 98 per cent, of the 

 dilepti tested, 70 per cent, forming three or more vacuoles; and 

 that Colpidium was ingested by 99 per cent, of the dilepti tested, 

 84 per cent, forming more than one vacuole. It is consequently 

 evident that these organisms are ingested in large numbers by the 

 majority of the dilepti tested. 



