574 Acton.— Coccomyxa subellipsoidea, a new 
Multiplication takes place by oblique fission, the mother-cell dividing 
into two, or occasionally four daughter-cells, which are exactly similar to 
the parent cell (Fig. 2). 
Reproduction takes place by the formation within the mother-cells of 
four, or rarely eight, non-motile gonidia, which are nearly spherical 2-4 p, in 
diameter, and arranged either in the form of a tetrad or all in the same 
plane (Fig. 3). These may be formed in rapid succession, and as the 
gonidia do not at once separate, subspherical aggregates consisting of 
a large number of cells sometimes occur (Fig. 4). Also by the formation of 
macro- and microzoogonidia, 2, 4, 8, or 1 6 of which are formed within the 
mother-cells. 
Cultures. 
In order to obtain, if possible, other stages in the life-history, cultures of 
the Alga were tried in 0-25 per cent., 0*5 per cent., and 0*75 per cent. Knop’s 
solution. In the stronger solution development was slow, the cells were small, 
and the culture assumed a brownish tinge. In the 0-25 per cent, solution the 
Alga reproduced actively by the formation of non-motile gonidia (Fig. 5), and 
the culture appeared to be a healthy one, although the cells showed some 
modification in structure. In this solution the cells increased very much in 
size and gradually became spherical, frequently attaining a diameter of 14 \x 
(Fig. 6). The chloroplast, which was crowded with large granules of starch, 
was no longer small, and in extreme cases appeared to cover the whole 
interior of the cell-wall. A large pyrenoid with a distinct starch sheath was 
present in each cell, and was quite visible without treatment with iodine 
solution. Sometimes two, and rarely three pyrenoids were present (Fig. 7). 
This would indicate that the number of pyrenoids present is not 
constant, but is dependent on nutritive conditions. Further, in the 
culture in 075 per cent. Knop’s solution, where development was slow, 
a pyrenoid could only be detected in a few cases, even after treatment with 
iodine solution. Thus it would appear that the presence or absence of 
pyrenoids, or the number present in the chloroplast are characters of no 
value from a systematic standpoint. 1 
Formation of Zoogonidia. 
At the end of six months, material from the culture in 0-25 per cent. 
Knop’s solution was transferred to a block of sterilized sandstone, standing 
in a culture dish with a layer of water at the bottom : in order to see whether 
1 These and many other observations relating to the occurrence of pyrenoids in chloroplasts of 
the Protococcoideae are entirely opposed to the views advocated by Schmitz, Schmidle (in Ber. 
Deutsch. Botan. Ges., Bd. xix, 1901, p. 24), and others, that the presence or absence of pyrenoids is 
sufficiently constant in the chromotophores of the lower types of Green Algae, to be utilized for 
specific and even generic distinctions. 
