734 ROBERT MCCARRISON. 
of encysted amoebe during the earlier phases of their 
development. 
At the time of encystment there is one nucleus present (text- 
fig. 10). This nucleus divides into two daughter-nuclei (text- 
figs. 11, 12). I have not been able to trace the complicated 
series of nuclear changes described by Schaudinn in E. coli 
and by Wenyon in H. muris as occurring at this stage, 
though I have seen a large number of amcebe. The two 
daughter-nuclei lie most commonly side by side (text-figs. 11, 
12). At this stage they vary greatly in size. I have seen them 
so large their diameter almost equalled half that of the cyst 
containing them. I have observed in one case a division- 
figure corresponding closely to fig. 73 of Dobell’s paper (8) ; 
unfortunately the specimen could not be drawn. In text-fig. 
13 the two nuclei have separated to either side of the cyst. 
Division of the two daughter-nuclei takes place, and text-fig. 
14 shows that one nucleus has proceeded to the second division 
before the other. It has been difficult to find examples show- 
ing four nuclei; text-fig. 15 shows a further division of the 
nuclei into five. The ultimate division into eight is shown in 
text-fig. 16. The cyst-wall eventually becomes thickened as in 
text-fig. 17, Division of the protoplasm around the nuclei has 
never been seen. Very rarely a form showing more than 
eight nuclei is met with (text-fig. 18), but it is so rare that 
we must regard it as abnormal. 
It is evident that the animal here described corresponds 
very closely to the Entamceba coli of Schaudinn and to the 
Entamoeba muris of Wenyon. The descriptions, however, 
do not correspond as regards the hyaline body, which is so 
characteristic of this organism; nor have I been able to trace 
in it the nuclear changes described by these observers. 
Amoeba II. 
Amoebee of this species are exceedingly plentiful in some 
vases ; aS many as three or four are often found in one field 
of the microscope. ‘hey may occur alone or in association 
