ACCOUNT OF THE GERM-CELL CYCLE 27 
a small amount of the surrounding cytoplasm, 
from the others, thus becoming a swarm spore. 
The swarm spores escape from the mouth of the 
parent cell; whereas the two primary nuclei and a 
portion of the cytoplasm not used up in the forma- 
tion of the swarmers die. The swarmers are not 
all alike, being of two sizes; the larger, which may be 
called macrogametes, and which correspond to the 
eggs of the Mrrazoa, fuse with the smaller micro- 
gametes. The zygotes which result develop into 
normal Arcelle. The swarmers may be supposed 
to represent the germinal protoplasm, of which, as in 
metazoan germ cells, the chromatin content may be 
considered the essential portion. The conditions 
during reproduction in other Protozoa may also be 
explained in this way, so that germinal and somatic 
protoplasm can be distinguished as in the Mrtazoa. 
The discovery of the chromidia in Protozoa 
led to the formulation of the hypothesis of binu- 
clearity. Believers in this hypothesis maintain 
that each cell contains both a somatic and propaga- 
tory nuclear material which, as a rule, are united 
into one amphinucleus. The somatic nuclear ma- 
terial controls vegetative functions; the propaga- 
tive portion serves only for the propagation of new 
individuals. Separation occurs rarely except in 
certain Protozoa, where, as in Paramecium, the 
propagative substance is represented by the micronu- 
cleus, the somatic by the macronucleus. Since the 
chromatin is the essential substance concerned in 
the binuclearity hypothesis, the term dichroma- 
