432 Mr Dobell, On the Intestinal Protozoan 
karyosome, consisting of a few loosely-packed chromatin granules 
in the middle of the nuclear network. The amoeba then rounds 
itself off and forms a cyst membrane, which is at first very thin. 
Inside the cyst, a large vacuole makes its appearance, and a 
considerable quantity of a chromatin-like substance is to be seen 
lying in the cytoplasm. It appears to be extruded from the 
nucleus. The nucleus soon divides into two by a kind of primitive 
mitosis with the formation of a characteristic spindle figure. The 
daughter nuclei, which are much smaller than the original 
nucleus, divide once more, so that four still smaller nuclei are 
present in the cyst. In this condition the cyst remains for some 
time, each of the four nuclei having the appearance of a ring 
with a central dot of chromatin. Subsequently the chromatic 
bodies in the cytoplasm are extruded, and the vacuole disappears. 
The cyst-wall thickens and becomes yellowish, and the four nuclei 
undergo no further change. These are the permanent cysts which 
probably serve for the infection of other frogs. From the re- 
semblance between the nuclei in the cysts and the nuclei in the 
smallest amoebae, it may be suggested that the cyst, on reaching 
a new host, liberates four small amoebae, just as the cysts of 
E. coli liberate a brood of eight. 
Many of the cysts, whether liberated in the faeces or taken 
from the large intestine, appear to degenerate. 
In Entamoeba ranarum, therefore, a very different series of 
events from those observed in E. coli and E. muris is to be seen. 
I have seen absolutely no indications whatever of an autogamy 
inside the cysts, as in the case of the two forms above mentioned. 
Although appearances similar to stages in autogamy are to be 
found — e.g. the two nuclear spindles during the second division — 
nevertheless, they have a very different significance. I cannot, 
therefore, in any way confirm the recent statement of Hartmann 
that an autogamy probably occurs in this form. 
The amoeba-form of Chlamydophrys differs from Entamoeba 
chiefly as regards its nucleus. This consists of a large central 
mass of chromatin separated from the nuclear membrane by 
a clear zone. 
The amoebae do not usually escape from the cysts in the frog, 
but do so after they have been liberated in the faeces. The 
amoeba-form subsequently develops a shell, becoming the typical 
Chlamydophrys — as already described by Schaudinn. 
C. Other Protozoa. 
Among the other Protozoa in the frog, I may record the 
presence of a hitherto undescribed Coccidium, which I propose to 
name Coccidium ranae, n. sp. I have only succeeded in dis- 
