212 ARCHER, ON CYLINDROCYSTIS, 
phologically equivalent —that two cells only co-operate, whilst 
many spermatozoids may take a share in the fertilisation of 
a single oospore. I can only say that these objections refer 
to conditions which seem to be in a measure accidental, and 
unessential in a physiological point of view. The mechanism 
of conjugation, if I may so express myself, does not require 
the special organization on the part of the primordial cells 
engaged in the act, which are found in Vaucheria, Sphzro- 
plea, some Cidogonia, &c. In these greater or less numbers 
of ciliated spermatozoids are produced—ciliated, probably, 
because they have a distance to travel—often in multitudes, 
to insure that some may ultimately find their way to the 
oospore ; whereas in the Conjugatze two cells about to con- 
jugate lie side by side, and are mostly joined by an inter- 
vening canal, formed by the walls of the parent cells, through 
which the protoplasmic contents are guided, and pass over by 
means of their own innate contractility, when acted upon by 
the marvellous impulse to coalesce the one with the other. 
Again, as to but two primordial cells co operating in the act 
of conjugation, whilst many (the spermatozoids) may unite 
with one (the oospore) in the other cases cited, the mechanism 
of conjugation, if no other reason, places a bar to this. I 
have, indeed, in such free forms of Conjugate as Closterium 
and Staurastrum, seen three individuals conjugated, forming 
a single zygospore—nay, it sometimes happens in Zygnema 
that the lateral processes of two joints mosculate with a 
single joit of a neighbouring filament, three cells thus co- 
operating in the conjugation. These, however, are quite ex- 
ceptional, perhaps even abnormal, cases. But this argument, 
even if adduced, I should regard as quite groundless, as it is, 
I presume, quite physiologically possible that one spermato- 
zoid might fertilise one germ-cell. Nay, even supposing that 
it always required the united co-operation of several sperma- 
tozoids to fertilise one germ-cell of so much greater volume 
than one of themselves, might it not be supposed that, by 
reason of the more nearly or altogether equivalent volume of 
the two conjugating cells, the force or potency would be 
sufficient without the co-operation of a greater number, not 
to speak of the mechanical impossibility in most cases, or of 
the unnatural dimensions which a zygospore must assume, if 
formed by the union of a number of so comparatively large 
ordinary cells? 
But, even though it be reiteration of already known facts, 
in pursuance of our argument, it will be well momentarily to 
carry on our examination of the phenomenon of conjugation 
from Cylindrocystis and Mesotenium into other genera of 
