228 THE VEGETABLE WORTDD. 
The Oscillatoria spiralis is a simple vegetable thread formed. by 
cells cohering at their extremities. The Oscillatoria nigro-viridis, 
shown in its natural state in Fig. 299, is a simple vegetable struc- 
Fig. 298. Two plants of Spherozyga Fig. 299. Three plants of Oscillatoria 
leyana. Nigro-viridis. 
Berkeleyan ign 
ture, consisting of cells united at their extremities like threads. 
Spherozyga Berkeleyana is a thread formed of simple cells touch- 
ing each other at each end. 
In the month of April the contents of certain small cells beaks 
modified so as to give a spongy appearance, first by the multiplica- 
tion of these small cells (Fig. 300, 2), than by the condensation of 
the green matter and grains of starch, like the figure, 3, and by 
the dispersion of most of the small cells from 4 of the same figure 
‘where the great flattened cells represent the superposed cellules. 
Sometimes the same cells contain a great number of free globular 
masses (Fig. 300, 4). These masses are young and soft spores, 
elastic, and destitute of membrane. 
Long before the contents of these cellules have submitted to the 
transformations indicated, the membrane proper to the cellules 
_ presents small openings at various points, whose diameter varies 
from 1-300th to 1-500th part of a line (Fig. 300, 4 and 5, 2). 
But all the cellules of the same filament of Spheroplea 40 
not present the same modifications which we have described, 
and which are finally converted into sporanges, filled with a mul- 
titude of spores. Phenomena of a very different nature occur i 
the meantime. The rings interposed between the uncoloured cell 
become reddish, and the grains of starch which they contain dis 
appear (Fig. 300, 5, a). Sometimes the orange-coloured matter 
is organised in an infinity of short corpuscles, arranged in @ cone 
fused mass. The rings are decomposed, and suddenly one of the 
corpuscles is observed to plunge into their substance, disengag® 
itself, and move in the cellular cayity; then other corpuscles af 
increasing numbers repeat the same phenomena. The movemen 
