98 MR. H. M. WARD ON THE STRUCTURE, DEVELOPMENT, 
distinguish them by any features of size, shape, or colour. Тһе chief differences I have 
been able to discover are, that the former (zoospores) slip out slowly from the orifice of 
the ovoid zoosporangium, and do not assume the fusiform state with jerky motion of 
the latter, but glide slowly about with the two long cilia widely divergent from the sub- - 
globular body of the zoospore. The act of emergence has been witnessed several times 
(figs. 35 & 36). 
The globular zoospores often remain just outside the empty case, as if embedded in a 
gelatinous matrix, their cilia feebly moving for some time (Pl. XX. fig. 38). So far as 
I could discover, after much search and observation of numerous cases, no conjugation 
ever occurs. The contents of the zoospore resemble those of the similar bodies first 
described—finely granular protoplasm, with small orange-coloured oily particles, and 
about twenty or more pale ovoid granules of unknown though apparently amyloid 
nature. In water many of the zoospores swell up in a vesicular manner and burst, the 
granules dancing in Brownian motion. It not unfrequently happens that the free 
zoospores become attached to the sides of the thallus-hairs, and their further development 
can be watched without much trouble; after some days each becomes pale apple-green, 
the amylaceous and other particles apparently becoming absorbed by the cloudy proto- 
plasm (fig. 37). In most cases a delicate but distinet limiting membrane is now formed, 
and a pale cloudy nucleus-like body can sometimes be deteeted in the centre of the mass. 
In this stage the zoospores are often to be seen on the epidermis of the leaf of Michelia ; 
and by artificial sowings I have obtained them on Coffea and Anona. Their germination 
has already been described (p. 92). 
Inthe rainy season, when the fertile hairs are especially abundant, the above-described 
zoospores become scattered widely over the leaves; and within a few weeks afterwards 
one finds the young disks, described above (p. 92), appearing in very large numbers. 
From Ше results of cultivation, and from the above facts, it appears fair to infer that this 
zoospore is always the originator of those disks; nevertheless І am not in a position to 
affirm more than that the cultivated zoospores come to rest, turn green, and commence 
to divide as described, whereas those obtained from the thallus-cells do not. 
Nothing that can be construed as a sexual process has been observed by me, either 
prior to or during the evolution of the “fertile hair" or afterwards; I therefore feel 
obliged to conclude that we have in these zoospores the asexual propagating bodies of the 
Alga. Nevertheless it seems highly desirable that more extensive cultivation than I nave 
been able to make should be carefully undertaken, to determine finaly whether the 
. zoospores from the thallus are really incapable of development, and, if not, whether they 
have any relation to the origin of the “ fertile hair” or to the zoospores produced from it. 
This seems in the last degree important; for it is impossible to believe that the (so far 
аз my experiments go) non-germinating zoospores have no function, on the one hand ; and, 
on the other, it does not appear probable that both forms of zoospore are asexual repro- 
ductive bodies, supposing further investigators succeed in bringing about their germi- 
nation. 
It has already been said that I am not able to regard the latter as zoospores produced 
_ from a fertiiized ооѕрһеге. Ifthey are finally shown to be incapable of germination, they 
