An Investigation of a Species of Saprolegnia. 315 
consists of a single cell, oval in outline, with a continuous cell- 
wall. When mature it is easily separated from the hypha. Some 
forms are more elongated and have one or more dense protoplasmic 
septa. The normal method of germination, when placed in new 
food material, is as a vegetative bud. 
(2b). The true “ resting sporocyst ” is also borne terminally 
on a hypha and usually consists of more than one cell (Figs. 13, 14), 
in some cases of a whole chain of cells—in old cultures as many as 
ten cells have been found in a chain (Figs. 11, 12). It does not 
separate easily from the hypha. The normal method of development 
when placed in a new food medium, is to develop into sporocysts 
and to discharge zoospores in basipetal succession. 
(3) . Multiple sporocysts, referred to by several authors, were 
always formed in old cultures, and developed first as resting sporo¬ 
cysts, no discharge taking place till they were transferred to a new 
liquid medium (Figs. 13, 14). 
(4) . Chlamydospores were found on a culture on a fly in 
haemoglobin and peptone solution, made up according to Kauffman’s 
formula. They closely resembled gemmae in appearance, and many 
were found detached from the hyphae. On germination they 
produced a short filament terminating in a sporocyst discharging 
motile zoospores (Figs. 19, 20). Some cases were observed 
where a secondary gemma was found in place of the sporocyst. 
The cases so far described, (2a), (2b), (3) and (4), merely indicate 
various phases in the life-history of a genus. They do not show 
any generic differences. The other cases now to be described all 
show some modification of the sporocyst and method of discharge 
or germination, characteristic of the various genera. All the cases 
were observed in hanging drop cultures on various media made from 
the stock pure culture. 
(5) . Leptomitus-type of sporocyst. On a two days’ old hanging 
drop culture on the skin of fish in distilled water, two forms of 
sporocyst were found on the same mycelium. The first form was 
the ordinary Saprolegnia-type (Figs. 1, 2), the other form was a 
very long slender sporocyst (Figs. 24, 25), with a single row of 
zoospores, the method of discharge being either terminal or lateral. 
The shape of the sporocyst and the formation of the zoospores in a 
single row closely resemble the normal form of the genus Leptomitus. 
(6) . Pythiopsis-type of sporocyst. In a hanging drop culture 
