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A. E. Lechmere. 
cilia grow out, they show a rhythmic undulating motion, and the 
whole spore is seen rocking within the sporocyst. 
The mature zoospores show one to three vacuoles, one or more 
of which show rhythmic contraction. A slight process grows out from 
the sporocyst, through which discharge will take place, the cellulose 
cap of the process becomes faint in outline as the front spore 
approaches it, and finally disappears. Discharge then occurs 
through the opening. In some cases the spores seem to press 
against the wall to cause it to open outwards. In Saprolegnia the 
early spores swarm out very actively, but the later ones as they 
move out are very inactive, and sometimes the last one or two do 
not leave the sporocyst. 
Asexual Reproduction in Species Under Observation. 
In the species with which the present investigations have been 
carried out the most common type of sporocyst was that of a 
Saprolegnia with diplanetic zoospores ; this has been taken as the 
typical form for the species. Besides this typical form eight variants 
on the normal type have been found to occur in the various 
cultures under different conditions. 
The cases observed were as follows:— 
(1). Typical Case. A small piece of fish (or other medium) 
bearing vegetative hyphse, was mounted as a hanging drop culture 
and the subsequent development followed under the microscope. 
After growing vegetatively for a time apical growth in the hyphse 
becomes arrested by the formation of terminal sporocysts. All 
details in connection with the formation of these sporocysts agree 
exactly with the account already given as typical for the group. 
The discharge is apical, the zoospores are motile at the time of 
discharge and show, encystment after a period of active swarming 
(PI. 1, Figs. 1—4). The first motile stage was found to last for a 
period varying from five to ten minutes. After encystment the 
spores rested for a much longer period. The shortest resting period 
observed was six hours. The more usual time appeared to be from 
twelve to eighteen hours. At the end of the resting stage the 
zoospore within the wall of the cyst protrudes as a small bud 
(Figs. 5—7); this bud increases in size and soon a line of 
separation can be seen between the zoospore and the inner side of 
the wall. The whole body of the zoospore is very contractile and 
has to squeeze through the very small opening in the cyst wall. 
This whole process was found in a great number of cases to take 
