1916] Wilson: On the Life-History of a Soil Amocha 257 



nuclear chromatin (pi. 19, figs. 33, 34). Sometimes the buds have few 

 granules (pi. 19, figs. 32, 36), but they may have many. Later these 

 go to form the characteristic nucleus, which is not organized until after 

 separation takes place (pi. 19, figs. 27, 28, 31). The cutting off of these 

 buds has not been observed, though they have been watched for more 

 than an hour at a time. But the evidence indicates that this process 

 does occur in the multiplication of this species of amoeba. Since no 

 bud in situ has ever been found with a small nucleus, but small 

 amoebas are found without nuclei and with chromidia, slightly larger 

 amoebas with small nuclei and few chromidia, and small amoebas with 

 large nuclei and no chromidia, it is evident that the nuclei are formed 

 from these chromidia after separation takes place and that as nuclear 

 formation takes place there is an increase in size of both nucleus and 

 cytoplasm and a progressive disappearance of the chromatin. 



The other form of budding, which is endogenous, is occasionally 

 found in this species. It has been noted by me only in binucleate forms 

 and occurs by the internal con.striction of the cytoplasmic mass around 

 one of the two nuclei. The fluid-filled space gradually enlarges until 

 it severs the internal bi;d from the parent mass. 



It is evident that endogenous budding does not often occur, at least 

 in cultures, since it has been observed in but three preparations, and 

 even in these in only a very few individuals. There was in no ease 

 more than one bud, though Wherry (1913) figures for this species one 

 or two, and IMiss Hogue (1914) in Vahlkampfia calkensi from one to 

 three. Liston and llartin (1911) also figure endogenous buds in "large 

 amoebas from liver-abscesses," in which in the early stage of bud- 

 formation there are chromidial strands. These later condense to form 

 the nucleus of the bud. This same process is suggested by my figures 

 29 and 35, plate 19. However, a complete sei-ies of the stages in this 

 process has not been found in my material, but so far as observed it 

 does not seem to differ from that which the above investigators have 

 described. A portion of the cytoplasm (pi. 19, figs. 29, 30, 35) con- 

 taining a nucleus is separated from the rest of the cytoplasm within 

 the amoeba and finally lies entirely free within a vacuole. After this 

 process it is probable that it is ejected from the amoeba, though there 

 has been no absolute evidence that this occurs, except that small 

 amoebas are found in the preparation. There is no direct evidence of 

 the origin of the endogenous buds by chromidial formation nor of their 

 separation as a phase of mitosis. 



