314 PROCEEDINGS OF THE ACADEMY OF [1883. 



active, and the parent mass still in active motion. On the fol- 

 lowing day I was unable to detect them, and as to their subsequent 

 history I know nothing. 



To characterize the phenomena as described above, I propose 

 the term " Reproduction by Partial Dissociation." Reproduction 

 by fission, gemmation, conji^ation and en cy station have all been 

 observed in the ciliated infusoria ; and some of the older writers, 

 such as Ehrenberg and others, have described a mode of increase, 

 in which the substance of the body breaks up into a number of 

 fragments, each of w^iich is capable of becoming a distinct indi- 

 vidual. This process they called difBuence, but Stein and other 

 more recent observers have denied the existence of this process, 

 claiming that it was merely a form of increase from enc3'sted 

 forms. The phenomena as exhibited by Amphileptus fasciola 

 seem to be quite different from those described as occurring in 

 diffluence, and it certainly was not a case of encystation. I have 

 been unable to find any account of reproduction in the infusoria 

 resembling that described above, and I therefore place the facts 

 on record, in order that the attention of other observers may be 

 directed towards the verification of the phenomena and views 

 expressed above. 



