THE ZOOCHLORELL/E OF FRONTONIA LEUCAS. 87 



In his work on the zoochlorellae of Paramecium bursaria, 

 Dangeard found that starch granules were abundant in the 

 zoochlorellae and it was his belief that the host appropriated 

 these starch granules as food, though he was unable to demon- 

 strate this. 



In this work on the zoochlorellae of Frontonia, starch granules 

 were found to be abundant in the zoochlorellae, but efforts to 

 show that they were ever taken into the food vacuoles of the 

 host have thus far been unsuccessful. 



SUMMARY. 



1. Frontonia with zoochlorellae require a medium of greater 

 stagnation and putrefaction than Frontonia without zoochlorellae. 



2. Frontonia may be freed from their zoochlorellae by a gradual 

 transference from their natural habitat to a medium of fresh 

 spring water. 



3. The number of zoochlorellae in Frontonia may be increased 

 by increasing the degree of stagnation and putrefaction of the 

 medium in which they live. 



4. Frontonia harboring zoochlorellae are more resistant to 

 media of greater osmotic pressure than are free specimens. 



5. The difference between the hydrogen ion concentration of 

 media in which Frontonia with innumerable zoochlorellae are 

 found and media in which Frontonia with no zoochlorellae are 

 found, averages 0.3. 



6. With an increase in the number of zoochlorellae there is 

 a corresponding increase in the hydrogen ions, and conversely. 



7. The ability of Frontonia harboring zoochlorellae to live in a 

 greater concentration of dextrose than Frontonia without zoo- 

 chlorellae is correlated with a greater hydrogen ion concentration 

 caused by fermentation of the dextrose. 



8. Efforts to induce Frontonia without zoochlorellae to gain 

 them were unsuccessful. 



LITERATURE. 

 Bary, E. de. 



1879 Le symbiose revue intern, des Sciences, tin. 

 Bouvier. 



Loc. cit., p. 139-140. 

 Dangeard, P. A. 



1901 Zoochlorellse of Paramecium bursaria. Le Botaniste. 



