LIFE HISTORY OF A FILIFORM ALGA. 
03 
subsequently reabsorbed, and tlie four cells lie still and motion¬ 
less. After a short time they break at one end by a circular 
slit, and the apex separating becomes elevated like a lid. 
Through this opening the contents emerge in the form of an 
oval zoospore, paler at the foremost end, which is furnished 
with movable cilia. Thus four active zoospores are normally 
the produce of one oospore, and these are in all respects 
similar in size, form, and movement to those we have seen 
originating male organs, or produced, asexually, from the 
cells of the filament. From this point, the same process is 
repeated. The zoospores move about freely for a time in the 
water, they then gradually become more sluggish, finally they 
become still, the pale end is directed downwards, the cilia are 
absorbed, an expansion like a radicle is formed, and by this it 
is fixed. Then the upper portion elongates, the apex becomes 
a growing point, a septum cuts off the first new cell, and a 
3 r oung plant has fairly started on its career, to produce in its 
turn its own oospores, androspores, and asexual zoospores, 
even as its parent had done. 
We have now traced the life history of (Edogonium cras- 
siusculum, and, as far as we can judge, the cycle seems to be 
tolerably complete. We have had to guess at nothing and 
to assume nothing; the continuity is unbroken, and, strange 
as some of the phenomena may be, there is no offence against 
our judgment or our experience, and no reasonable foundation 
for doubt. 
To such a story it is unnecessary for me to append a moral 
at the end, such as we find in all goody-goody books for 
goody-goody boys and girls. Yet, I cannot help asking you, 
as naturalists, whether organisms about which such a history 
can be written do not deserve a more widely extended study 
than they as yet receive. Any of you may take a phial in 
your pocket and trudge to Sutton Park. If you have none 
other, utilise that which held your last “ black draught.” If 
that fails, be content with a pill box, or even a square of 
brown paper. There are certainly some half a dozen species 
to be found there. By perseverance and experience you may 
find them all, and trace out their history. You require no 
elaborate apparatus, only three things, all of which are essen¬ 
tial :—(1) A microscope ; (2) ability to use it; and (3) a good 
resolution. With these no one needs to fail. 
This may be a humble organism that I have brought to 
your notice, it may be a low form of vegetable life, one of the 
lower Cryptogamia—facts which I am not prepared to dispute. 
They live, vegetate, thrive ; some in rather dirty places, col¬ 
lecting their own food, supporting themselves by the exercise 
