444 Dr. G. C. Wallich on Amoeba villosa 



other varieties, but from the specimen itself having ultimately 

 assumed all the characteristics of A. radiosa immediately after 

 the termination of the appearances depicted in the figure. 



Judging from the appearances at first presented, I naturally 

 expected the occurrence of binary division — two lobes instead 

 of three being then only visible ; and accordingly I directed 

 special attention to the share taken in the process by the nucleus 

 and contractile vesicle. But these bodies gave no sign of partici- 

 pation beyond passing several times, during the ordinary con- 

 tractile movements of the lobate masses, through the connecting 

 isthmuses, either into the same or into separate lobes. No 

 pressure was exerted, nor was the form assumed due to the 

 juxtaposition of foreign matters. Nevertheless fission did not 

 take place ; and after an hour's apparently incessant struggle to 

 part company, during which period the lobes and isthmuses 

 did not materially alter their relative proportions, the three 

 portions gradually coalesced, and the specimen moved away 

 energetically, putting forth the tapering and radiate pseudopodia 

 supposed to be distinctive of Amoeba radiosa. 



It is no doubt true that the unity of the nucleus may have 

 interfered with the consummation of the process. But here, again, 

 generalization fails to some extent; for on two occasions I have 

 seen Amoeba villosa divide without the nucleus being involved. 

 In both cases the villous patch was nearly equally parted ; only 

 that half of the body, however, which retained the nucleus 

 moved about vigorously and exhibited the typical characters, 

 whilst the other half assumed a spherical shape, and merely 

 oscillated very slowly and steadily to and fro on the same spot, 

 without projecting pseudopodia, or materially altering its out- 

 line. 



In these examples, also, all undue pressure was avoided ; and 

 the extrusion of nearly the whole of the effete alimentary par- 

 ticles by each half — which I have frequently found to be the 

 precursor of the process of fission — took place almost at its 

 commencement. 



The third example I have to mention occurred in a large 

 specimen of Antinophrys Eichhornii which I disengaged from the 

 side of the vessel to which it was adhering, and carefully placed 

 for observation in a watch-glass. When removed, it was appa- 

 rently undergoing the common process of binary division. At 

 all events, whether that process was going on or the case was 

 one of " zygosis " or amalgamation of two individuals, it is quite 

 certain that there was a partial, but nevertheless effective, 

 fusion of the sarcode substance at the constricted portion. In 

 this species, as shall presently be shown, the nuclear bodies are 

 small and, generally speaking, multiple. Hence no informa- 



