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At this stage a septum is suddenly formed at the base of the
sporangium which is henceforth an independent cell, completely
separated from the parent tube. Even before this septation there may
be noticed in the rostrate elongation directed towards the hornlet, the
gradual accumulation of a colourless fine granular substance, of the same
Mture as that with which the wall of the parent tube, and the
sporangium is lined on the inner surface, which has already been termed
the “ cutaneous layer.” This accumulation in the fore part of the
rostrum is continued after the formation of the septum between the
sporangium and the tube, and in oonsequenoe of its continued increase,
the remaining contents of the sporangium are by degrees pushed back
towards the base. Whilst these phenomena are bemg manifested in tne
sporangium, the hornlet also undergoes remarkable changes. In its
apex, the contents, owing to the disappearance of the ohloropliyll, have
become almost colourless, more or less. Thus the point of the hornlet,
like that of the sporangium, appears at this time to be filled with a
colourless substance, which is not constituted by an accumulation ot the
cutaneous laver, but manifestly arises from a molecular change
associated with an alteration of form and colour in the contents previously
existing at the apex. So soon as the contents at the point ot the
hornlet have thus become colourless, they appear to be constituted of a
very fine-grained granulose mucous substance. As soon as the tjans-
formation of the contents has taken place, the colourless apex of the
hornlet is suddenly separated from the lower green portion by a septum,
and is thus transformed into an independent cell, without communication
with the parent tube. The point at which the septum is formed is_ not
very determinate, the portion out off being sometimes larger, sometimes
^™After the formation of the septum in the hornlet the colourless mucous
in its apex gradually assumes a more determinate form, and at
this time a large number of minute, perfectly colourless, rod-like
bodies may be readily perceived crowded together irregularly, and
as it were imbedded in the surrounding mucous. Close observation
will disclose an indistinct movement exhibited even thus early
by some of the little rods, from which their destination may be
^’^Thri’perfeoting of the hornlet coincides with that stage of development
of the sporangium at which tlie accumulation of the cutaneous layer in
the anterior part of the rostrum has attained its greatest extent, and
these conditions immediately precede the act of impregnation, which is
effected in the following manner
The pressure within the sporangium, especially in the direction ot tne
rostrum, becomes greater and greater in consequence of the continued
increase of the cutaneous layer in the fore part, until ultimately the
membrane is ruptured exactly at the point of the rostrum, and allows a
portion of the cutaneous layer to escape. The extruded poidion
becomes detached, and assumes the character of a drop of mucous, winch
remains lying near the opening of the sporangium, and ultimately
perishes The accumulation of the cutaneous layer in the fore part of
the rostrum, and the escape of a portion of it, are merely the mechanism
by which the opening is produced in the sporangium destined for the
admission of the spermatozoids. Immediately after the formation of
this opening in the sporangium, and in remarkable coincidence with
the escape of the cutaneous layer through the rostrum, the hornlet opens
at the apex, and pours out its contents. Innumerable excessively minute
rod-like corpuscles ( 005 mm.), mostly isolated, escape at once through
the orifice. Those already isolated exhibit an extraordinarily rapid
movement in all directions, and those still imbedded in the mucous do not
become detached until afterwards, when they follow the others with,
equal rapidity. The field of view is soon covered with mobile oorpusoles,
'i.Iili
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In great number (20, 30, or more) they enter the neighbouring orifice
of the sporangium, which they fill almost entirely, penetrating through
the portion of the cutaneous layer remaining, whicn, though without
any definite boundary, offers a solid resistance to their further penetration
into the sporangium. The corpuscles continue thus to struggle forwards
into the cutaneous layer for more than half an hour, bounding against
its outer surface they retreat, again push forwards, again retreat, and
so on, in an uninterrupted succession of assaults and retreats.
After this commotion has lasted some time, an abrupt boundary line
suddenly appears in the outer aspect of the cutaneous layer, the first
indication of a tunic forming around the contents of the sporangium
which were before bare. From this moment tlie mobile oorpusoles are
separated from the cutaneous layer by a membrane which eftectually
prevents their further action upon the contents. They continue, it is
true, to move to and fro, and this movement often lasts for hours
together, hut at last they perish in the rostrum itself. Even after the
lapse of several hours the dead oorpusoles may be seen in the rostrum,
lying on the front of the sporangium, until at last they are completely
dissolved, and all vestige disappears.
The cutaneous layer surrounding the green contents of the sporangium
becomes transformed, after impregnation, into the coat of the true spore,
which, thus formed, represents a large cell occupying the whole ot the
sporangium, surrounded on all sides by the persistent tunic, which is
open in front and prolonged into the rostrum. ... . r . - __
In this condition the spore remains for some time longer without bemg
thrown off from the parent tube on which it was produced, but the
colour of Its contents gradually becomes paler and paler. The spore is
at last rendered quite colourless, and presents In its interior only one or
more largish dark brown bodies. When it has lo,st all colour it is
detached from the parent tube, in consequence of the decay or
membrane of the sporangium enclosing it. After some time, say thiee
months, the spore suddenly resumes its green colour, and immediately
thereupon grows into a young Vaucheria exactly resembling the parent
An’abstract of the memoir from which the above details were obtained
was published in the “ Quarterly Journal of Mioroscopioal Science for
^^DurinltL'preseiff winter Mr. Frederic Bates, of Leicester, has called
our attention to some plants of F. smiiis. taken from beneath tte
in a pool. The first feature wliioli presented itself was the septation of
the threads, many of them being divided into numerous articulations
three or four times the length of the diameter m the upper portion of the
thread, but longer below. This unusual septation, as it appears to be,
was general throughout the gathering, but the threads beaimig oogonia
were more rarely divided, but sufficiently so to remove any doubt ^ to
the threads being genuine threads of which at fiist we mu»t
confess to have doubted. The question which next arose was as to the
purpose for which this septation iiad taken place, and an answer sug-
eested itself in the collection of the cytioplasm into denser masses
towards the centre of the cell, with most evident differentiation into oval
bodies, resembling zoogonidia m course of formation. The *1“ ® “i
observation has been short, but long enough to raise a suspicion in our
minds that another form of fructification, by means of zoogonidia, takes
place in Vaucheria, and the occurrence of germuiating spores in various
early stages in the water in which the Vaucheria wa^ P®)?“ preserved,
lends strength to this suspicion. It is quite true that Vaucheria has
been often and patiently studied, and no intracellular swarm-spores
detected ; yet it maybe possible that, under oertam conditions, they may
be produced. We are patiently waiting in hopes of obtaining active
zoogonidia.
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