1909] ATKINSON—FUNGUS PARASITES OF ALGAE 331 
one direction and separating itself from the group by several milli- 
meters; then it is drawn back again to its fellows as if by a retractile 
cord; then another will separate in the same manner, only soon to be 
drawn back again. This pulling away and returning becomes more 
and more accentuated each time, until finally one of the zoospores 
makes its permanent escape, leaving the others to struggle still for 
freedom. One by one, or two or more at a time, they escape in this 
manner and whirl away. This mode of escape would indicate that 
there is no inclosing membrane. 
Before the escape of the zoospores, in cases where small portions 
of the zoospores have become separated, they may fuse or conjugate 
with the large ones again, but whether with the same one from which 
they were separated or with a different one could not be determined, 
since the gliding and rotary movement of the individuals and the 
mass would prevent absolutely the following of the separate ones 
through their various evolutions. DEBary® (p. 37, 1881) first 
observed a separation of portions of the protoplasm and their fusion 
again with the parent masses in the formation of the oospores of the 
Saprolegniaceae, and it has since been observed in the oospores by 
Hartoc? (p. 24) and Humpurey’ (p. go). It was first observed in 
the zoospores of the Saprolegniaceae by Rothert® (1887, also p. 322, 
1890; see also HaRroG, J. c.). When fusion did not take place before 
the zoospores made their escape from the group, the smaller portions 
would not then fuse with the larger ones, even if they came by acci- 
_ dent in contact with them, so far as I was able to observe. In other 
Cases the small portions of protoplasm might become partially 
separated from the larger ones, and the zoospores escape with a 
minute appendage attached either at one of the extremities or upon - 
°DEBary, A., Untersuchungen iiber die Peronosporeen und Saprolegnieen und 
os Grundlagen eines natiirlichen Systems der Pilze. Beitr. Morph. u. Phys. der Pilze 
431-145. pls. 1-6. 188r. 
7 Hartoc, M. M., Some problems of reproduction. Quart. Jour. Micr. Sci. 
33: ee 1892 
. REY, J. E., The Saprolegniaceae of the United States, with notes on other 
Species, ies Am. Phil. S Soc. 17:63-148. pls. 14-20. 1893. 
® RotHert, W., Die Entwickelung der Sporangien bei den Saprolognieen. Beitr. 
Biol. Pf. 5:2 291-349. pl. IO. 1 ne This paper first appeared in Polish in the Pro- 
ceedings of the Cracow Academ 17t 1887. 
