238 THE VEGETABLE WORLD. 
its progress is easily followed under the microscope. The elonga- 
tion of the filaments take# place, so to speak, under the eye. 
M. Thuret states that he has measured more than once an increase 
of three-twentieths of a millimetre (about three-eightieths of an 
inch) in an hour. 
Besides these non-sexual multiplications by zoospores, there has 
been recently discovered in the same plant a true sexual repro- 
duction, produced by the assistance of two distinct organs, borne 
at a little distance the one from the other on the filaments. The one 
B (Fig. 309, a) is a sort of short branch, 
re-curving as it were upon itself, like 
a snail, or small horn. The other, 8, 
is a sort of shell, light and thin, an 
Ssss= fashioned like a beak, which is ca 
Gg22soe S22" the sporange. These two organs are 
separated, the one from the other, upo® 
Fig. 309. Sporangia of the Vaucheria '2€ tube which carries them, by : 
Sint Peon getion: transverse chamber. In the interior © 
the sporange, and towards its base, certain green seeds are found, 
while towards the beak is a colourless matter, very finely granulated. 
At the extremity of the cornicule, which is bounded by a thin 
partition, a great number of small clubs are 
| SESS found, more or less surrounded by a colour- 
4 less mucilage. 
‘ Such is the state of things when fecunda- 
Fig. 310, Antheromoia tion takes place. At this moment he 
of the Vaucheria. of the sporange is broken at its tip, and t 
matter contained in this species of sac is poured out through 
the opening (Fig. 310). Immediatety after the sporange opens; 
the cornicle, by a marvellous coincidence, opens also at ey 
extremity, and pours out its contents. Innumerab e 
corpuscles of minute size, but retaining their club- : 
like shape, that -is to say, antherozoids, now ee 
from the cornicles. They penetrate the — 
opening of the sporange (Fig. 311), filling 1¢ a 
entirely. Arrived at the surface of the mucous 
anulous bed, which prevents them, by its pare | 
from penetrating further, they advance and retire, continuing "™" 
wolt 
Wo}, Ae! 
Fig. 311. Anthero- 
zoids penetrating 
the Sporangia. 
