S52 SYDNEY J. HICKSOK. 



fragment of the meganucleus ot" Euplotes cliaron does not 

 die, but fuses with the neAv meganucleus. A similar observa- 

 tion was made by Maupas on Euplotes patella. 



The investigation of the conjugation of Dendrocometes 

 described in this paper throws no new light on the important 

 question of the initial stimulus to syzygy. It is well known 

 that j\laupas was able to induce conjugation in several 

 species ot" Ciliata by a judicious withdrawal of food material 

 after a certain number of binary fissions; that he was of 

 opinion that in natural conditions it is the exhaustion of the 

 food supply which affords the main stimulus to the epi- 

 demics of conjugation. The views of Maupas have recently 

 received some support from the experiments of Prowazek 

 (22), who was able to induce conjugation by hunger in 

 Stylonychia pustulata. On the other hand, Joukowsky 

 (17) failed to induce conjugation by hunger in Pleuroti'icha 

 after experimenting for eight months and reaching the four- 

 hundred-and-fifty-eighth generation. 



I tried the experiment several times of isolating a number 

 of Gammarus bearing the Dendrocometes in filtered water 

 for six days or a week, and obtained in some cases sufficient 

 evidence that the Acinetarians were affected by hunger ; but 

 there were on an average neithei' more nor less pairs in 

 conjugation than in the Dendrocometes of the control 

 experiment. Starvation cannot be extended for more than a 

 week in this case, as the hosts soon die in the filtered water, 

 and their macerating bodies afford ample food again for the 

 epizoites. 



Dendrocometes itself is peculiar among Infusoria in that 

 it appears to be capable of feeding all through the process 

 of conjugation. Mr. VVadsworth and I have observed the 

 arms of conjugates catch food and pass it down into the body 

 protoplasm. Judging from the food granules as seen in 

 sections, the onset and progress of conjugation appear quite 

 indifferent to the condition of hunger or satiety. 



The following notes will illustrate this point : 



(The letter F in the third and fourth columns signifies that 



