330 BOTANICAL GAZETTE [NOVEMBER 
thread itself, in the latter cases usually arising from the outer con- 
vexity of a curved portion of the thread. The exit tube is about 2» 
in diameter and projects but a little way outside of the wall of the host. 
The tube develops quite rapidly. In observations on cell cultures 
where I have been watching for the migration of the protoplasm 
through the exit tube, cos ones have been observed to develop in 
two to four hours time. The 
end of the tube becomes gelati- 
nized and the protoplasm moves 
in a quite rapid stream through 
the tube, the small spherical mass 
of protoplasm at the mouth of the 
tube growing rapidly in size until 
all the protoplasm has passed 
through, which takes only a few 
seconds. In a few moments 
Wiha See i rotary motion begins, sow at 
Walker cae prosporangia, which are fSt. Soon the constriction of the 
sections of the thallus; B zoospores form- mass occurs in lines over the sur- 
ing at the apex of the exit tube; C zoo- face, in such a way as to divide 
or and small particles separated from he ua teee inta portio ns ac- 
cording to the size of the mass 
and the number of the zoospores to be formed. In this species I 
have not observed any inclosing membrane, nor any evidence that 
such a membrane exists, though Zopr (i. c., p. 149, 1884) describes 
and figures one. The constriction goes on from the surface toward 
the center, and soon the cilia are developed, their slow waving 
aiding in the slow but perceptible oscillatory motion of the mass. 
Plastic movements of the mass and the developing individuals 
also accompany the other movements. When division has become 
nearly complete, small portions frequently become constricted from the 
ends of the ovate to reniform individuals, the constriction becoming 
deeper and deeper, until in many cases the small portion becomes 
separate from the larger mass (jig. 5, C). These can be seen to be 
separate from the larger ones by the gliding motion of the zoospores 
over each other, and over the smaller bodies. The movements become 
more and more active, occasionally one zoospore pulling strongly in 
