Development of Vaucheria Resting-spores. 167 
time (in my experiments after about three months) the spore, 
which is readily recognizable by the red-brown nuclei in its 
interior, suddenly resumes its green colour, and immediately 
thereupon grows into a young Vaucheria, exactly resembling 
the parent plant. Close observation shows that the innermost 
layer, elongating, breaks through the thick outer membrane 
and becomes the young tube exactly in the same way as I 
have described the process of development in the germinating 
spore of Spirogyra.” 
On May 8th, 1901, I had under examination a quantity of 
one of the larger Vaucherta which had been gathered a 
fortnight previously and placed with water in a shallow dish. 
Much of the weed had died, but on and among the filaments I 
found a very large number of resting-spores. A quantity of 
these were on this day placed in a small wide-mouth bottle, 
loosely covered with a screw cap, merely to exclude dust and 
diminish the amount of evaporation. The bottle was half- 
filled with water, and was then left, not far from a window, on 
the end of a mantelpiece in my study. 
The bottle was at first opened only on two or three occa- 
sions for a brief examination of its contents. The spores 
were soon found to be undergoing the common kind of change 
—that is, were becoming decolorized into a whitish-grey 
mass of granules and vesicles, containing in its midst from 
one to four aggregations of pigment-granules. The pigment- 
heaps in this case were of a reddish-brown or reddish-orange 
eolour, though very frequently the tint is found to be of a 
blackish green. 
After an interval of several weeks, on July 4th, I examined 
_ the contents of this bottle again, and in the first portion of 
the deposit taken up with a pipette I found a number of the 
resting-spores germinating and giving birth to filaments. 
They were associated with other spores in their ordinary 
condition and others still in which different changes had been 
taking place. 
Both the resting-spores themselves and the filaments that 
had grown from them were lined, sometimes pretty thickly 
and at others very sparsely, with bright green chlorophyll- 
corpuscles. In regard to the filaments, the most common 
arrangement was that the single process sent out almost 
immediately divided into two at a very obtuse angle; at 
other times the division took place at some distance from the 
spore, while occasionally two filaments were seen coming off 
from the spore itself close to one another. Subsequently 
they branched and changed in diameter in a very iregular 
manner. 
