An Investigation of a Species of Saprolegnia. 311 
slowly towards the apex, causing the end to become densely filled 
with granular protoplasm and also a slight swelling of the 
walls. At first a gradual transition is seen from the dense 
granular protoplasm in the swollen end to the less dense proto¬ 
plasm of the basal hypha ; later on a clear line of division is seen, 
consisting of a band of hyaloplasm or clear protoplasm without 
any granules. This ring of hyaloplasm, by a process of conden¬ 
sation from its inner circumference, forms a transverse septum or 
disc sharply separated from the basal hypha. 
The sporocysts may he of three kinds :— 
(1) . Full sporocysts, usually very small and with no central 
vacuole. 
(2) . Normal sporocysts, with a thick parietal layer of proto¬ 
plasm enclosing a central vacuole. 
(3) . Starved sporocysts with a thin parietal layer enclosing a 
very large vacuole. 
The granular protoplasm of the sporocyst is at first uniform, 
but later shows a number of splits reaching from the central 
vacuole nearly to the wall ; the number of splits increases till a 
honeycomb network is formed with protoplasmic bridges traversing 
the strands of the network. Later these connecting strands 
disappear, leaving a number of spore-origins, each with one 
nucleus, as the meshes in a network. The spore-origins now 
contract, thus widening the space between them and severing any 
remaining protoplasmic strands. The surface of the origins now 
becomes smooth instead of granular. 
The origins now expand again and come into close contact 
with one another; some (Biisgen, Rothert) assert that fusion 
occurs, but in some cases a clear septum has been seen, reaching 
to the wall of the sporocyst. The origins now become spores. At 
this stage Rothert and Hartog describe the exudation from the 
sporocyst of a substance which is attractive to bacteria, accom¬ 
panied by a slight contraction of the sporocyst. As the spores 
become separated off vacuoles appear in each. In outline they are 
warty and often small pieces of protoplasm become separated off 
from them to fuse again later. A similar state of things is recorded 
by Rothert and De Bary as occurring during formation of the 
oospheres within the oocyst. 
Each zoospore now slowly develops two cilia. The front 
spore usually has its cilia directed towards the opening. As the 
