324 DR. T. GOODEY ON 



re-forming nuclei could be made out on focussing very carefully. 

 It can be seen from this figure that the reorganisation process 

 takes place earlier on the outer side of each nucleus than on the 

 inner side. I have not been able to distinguish any reticulate 

 arrangement in the linin particles which are laid down as the 

 process of reorganisation commences. The fission of the body 

 is now carried a little further, and the two daughter-organisms 

 are produced. There does not appear to be any connecting- 

 strand of protoplasm between the two products of fission, though 

 in all these stages this region is extremely difiicult to make out, 

 owing to the presence of large masses of adherent bacteria, 

 which I have purposely omitted from the drawings. 



The new karyosome now increases in size by the absorption of 

 the remaining fine granules of chromatin. It is no longer 

 possible to distinguish any spindle-fibres, and each nucleus 

 becomes rounded o&. The new nuclear membrane is apparently 

 formed from the zone of linin surrounding the new karyosomes, 

 and from this zone also the peripheral ring of feebly staining 

 granules is also produced. The only difierence between the 

 nucleus of the stage represented in fig. 63 and that of a full- 

 grown animal is merely one of size. 



(c) Encystation. 



On the same preparations which showed dividing animals, I 

 obtained a few stages revealing the process of encystation. The 

 first indication of this is the production of intensely staining 

 small round granules in the endoplasm, as shown in fig. 64. In 

 this animal I could discover very few ingested bacteria., and it is 

 evident that the normal process of digestion becomes suspended 

 with the beginning of encystation. There is practically no 

 difference in the appearance of the nucleus duiing the process of 

 encystation, and even when the cyst-membrane has become Avell 

 defined, as in fig. 65, it was still possible to distinguish all the 

 principal structures of the nucleus. The karyosome in the 

 encysting animals is rather smaller than in normal active forms. 

 As encystation proceeds, there is a gradual contraction of the 

 endoplasm round the nucleus, so that the ectoplasm is left as a 

 distinct region free from granules. This is particularly well 

 shown in fig. 64, where the line of separation between the two 

 constituents of the protoplast is especially marked. The animal 

 diminishes somewhat in bulk, and the cyst-membrane is laid 

 down around it. This later on becomes much corrugated and 

 indented, as shown in fig. 65. It is quite well defined at this 

 stage, but becomes somewhat thicker at a later period ; a point 

 which I have determined by the examination of empty cysts. 

 There does not appear to be an endocyst. In possessing deeply 

 stainable gi-anules, the cysts differ from those of Amoeba glebes, 

 in which Dobell describes non-stainable extremely refractile 

 granules. I do not know what the real nature of the granules 



