SCIENTIFIC SUMMARY. 
493 
hyaline covering. The cell-contents are composed, not of one, hut usually 
of four green masses, each surrounded by its cell-membrane. Sometimes, 
also, as it appears, abnormally, the masses are two or three in number. The 
four cells which proceed from germination possess an oval form, and their 
cell-membrane is hyaline. After the contents of the spore have emerged, 
there remains behind the outer membrane, enclosing the inner one. After 
the four cells have remained some time enclosed in the hyaline covering, this 
becomes resorbed subsequently, and the four cells lie still and motionless ; 
but after the course of a short time there sets in a remarkable change — the 
cells burst, namely, at one end, by means of an annular slit, and the apex, 
separated thereby from the remainder of the cell-membrane, becomes raised 
up like a lid. Through the circular opening the cell-contents now emerge, 
which, at the part turned towards the opening, is colourless. This apex 
moves with vigorous motion backwards and forwards, and, after the brief 
space of an hour, the cell-contents, in the form of a zoospore, leave their place 
of detention, which we now find to be a doubly contoured cell-membrane. 
The little zoospore wheels about in a lively manner with a circling move- 
ment, whereby the colourless point becomes directed downwards towards the 
mirror of the microscope. Its appearance is puzzlingly like that of an 
ordinary zoospore, and, like it, it possesses an oval form and a lighter apex, 
furnished with a crown of cilia, which during the motion is always directed 
forwards. After the course of some time the movements become faint, and 
finally cease altogether. The cilia disappear, and the light end becomes 
elongated into a root, which sometimes becomes formed into an organ of 
attachment, quite like that which is produced in the germination of the 
ordinary zoospores. The rounded end of the germinating zoospore acquires 
a little point-like apex, indeed, herein much resembling the ordinary zoo- 
spores. This young unicellular growth becomes divided by a transverse 
septum, and a little two-celled (Edogonium has now originated. 
Structure of the Anthers of the Aroidcce . — In one of our late summaries, we 
gave an abstract of a paper by M. Chatin in which it was stated that “ anthers 
which open by means of terminal pores are devoid of fibre-cells.” The general 
application of this expression has been denied by M. "Van Tieghem, in a 
memoir recently published upon the structure of the anthers in Aroidese, 
which latter, he says, is incompatible with such an arrangement as that 
alleged by M. Chatin. He gives the following example : — The sessile anther 
of j Richardia Africana has two chambers, each of which is further divided 
into two thecae by a thin longitudinal partition, which opens externally at 
the summit by means of a small vertical tube, hollowed out of the thick layer 
that the connection in expanding forms above the chambers ; beneath this 
pore the septum is resorbed to allow the chambers to communicate with each 
other. The inner wall of the chamber is lined when mature by a layer of 
prismatic cells, arranged perpendicularly to the surface, and provided with 
strong spiral bands. In each of the secondary chambers or thecae this 
layer of spiral cells ceases at the two borders where the septum arises ; here 
they curve a little towards the interior of the chamber, and come in contact 
through the medium of smaller cells with the corresponding layer of the 
adjacent chamber, thus forming with it two longitudinal crests. The other 
details of structure are too numerous for an abstract. It may, however, be 
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