3 r 4 
A. E. Lechmere. 
often observed growing through into the empty sporocyst (Fig. 8), 
where a new sporocyst would he formed. All the details so far 
described are typical of the genus Saprolegnia. 
The two commonest variations of this life cycle were the 
formation of gemmae or resting sporocysts and multiple sporocysts. 
The first variation is common to several species and genera and 
should perhaps he counted as part of the general life cycle. 
(2). Gemmce resemble the early stages of sporocysts before 
the cleavage furrows are formed, so far as their internal structure 
is concerned, but they differ in shape, being usually much shorter 
and having an oval outline (Fig. 15). They all show a central 
cavity or vacuole within a peripheral layer of granular protoplasm. 
The gemmae can rest in this condition for an indefinite period. In 
old cultures they easily become detached from the hyphae (Fig. 16) 
and can be found in great numbers in the liquid medium. This 
property affords one method of obtaining pure cultures, as gemmae 
can be separated and transferred to sterile plates of media in Petri 
dishes by means of a small pipette or a platinum loop. 
The subsequent development of the gemmae depends to a great 
extent upon the medium. If they are transferred to a rich food 
medium, such as beef extract, they invariably develop at once 
vegetatively (Figs. 17, 18), producing outgrowths from one or more 
points on their surface. Usually the germ tube is produced from 
one end of the gemma, and, branching freely, forms the new 
mycelium. If, however, the gemmae, are transferred from an old 
culture fluid to hanging drops of distilled water, most of them 
develop into sporocysts and discharge motile zoospores (Figs. 21-23). 
The shape of these sporocysts is rather different from those 
formed normally in the mycelium. The normal sporocyst has a 
very short process developed at discharge, while the sporocysts 
developed from gemmae develop a very long tubular process, 
which, in some cases, is so very long as to render the discharge of 
the spores very difficult. Many spores consequently remain within 
the sporocyst, where they may be r seen germinating. 
Most writers describe “ gemmae ” and “ resting sporocysts ” as 
identical, but although transitional stages can be found, the typical 
gemma can be distinguished from the typical resting sporocyst, as 
found in the cultures used in this laboratory. After examining 
numerous cases the following distinction could be drawn. 
(2a). The true gemma is formed terminally on a hypha, and 
