STRUCTURE AND LIFE-HISTORY OF COPROMONAS SUBTILIS. 99 
zygotes which continue to lead an active life instead of encyst- 
ing. But in this case, of course, the fusion of the nuclei is 
accompanied by an external remodelling of the cytoplasm (see 
fig. 27). 
It is a matter of some difficulty to make out the fate of 
cell-organs other than the nucleus during conjugation. From 
its behaviour during division the basal granule of the flagellum 
might be thought to play some part in the process of conjuga- 
tion. But although I have devoted a good deal of time and 
care in endeavouring to discover whether the basal granules 
fuse during conjugation I am still quite ignorant on the sub- 
ject. Appearances suggesting a fusion are sometimes seen, 
but it is impossible to attach much importance to them on 
account of their very small size and the numerous other 
granules which often fill the cytoplasm. In many stages, 
indeed, I have not been able even to distinguish the basal 
granule of the flagellum which has been retained. 
Regarding the reservoir and cytostome I am still uncertain. 
It appears to me that in both these structures one is absorbed 
during conjugation, whilst the other is retained and forms 
the permanent organella in the active zygote. Fusion does 
not appear to take place between the reservoirs, but one 
apparently collapses, leaving the other one functional. Two 
reservoirs may sometimes be seen until quite a late stage in 
conjugation (cf. Pl. 4, fig. 26). 
The food masses of both the conjugants get mixed up in 
the zygote. hey are all absorbed before encystment, so that 
the cysts have clear protoplasmic contents. I have not been 
able to follow out the fate of the basal granule in the cyst. 
I have observed an abnormal fusion of three monads, but 
have never succeeded in tracing out the result of such a union. 
This condition is depicted in Pl. 5, fig. 47. It can be seen 
that two of the flagella have disappeared, only the basal 
granules remaining. There is no reason to suppose that com- 
plete conjugation ever occurs between more than two monads. 
But the observation is of some interest from the fact that a 
similar “dreifache monstrése Kopulation” has been seen in 
