104 Chodat . — On the Polymorphism of the Green 
mother-cell by the absorption of the dividing walls within 
the latter, which is then to be compared to a sporangium 
with 4-8 or more zoospores. These are set at liberty by the 
rupture of the sporangium-envelope. 
In some cases, though rarely, the sporangial division passes 
into the G/oeocystis-stage or condition by the gelification of 
the wall of the mother- and daughter-cells ( Chi . pulviscnlus , 
Chi. intermedia). 
A very interesting condition is that which I have described 
in the case of Chi. intermedia 1 . We have here a reduction 
to a Tetraspora-\y pe, in which the cells are grouped in a 
single plane. By the further division of each of the four 
cells this stage is able to assume a very singular form, which 
I have named the larval stage. In this case each segmen- 
tation in the four cells is in a direction perpendicular to the 
division of the next cell. A similar mode of segmentation 
is well known in certain Volvocineae ( Volvox and Eudorina) 2 . 
I have observed it in all the genera of this family, and also 
in the lowest forms, such as Chlamydomonas. This condition 
has been called the Gonium-stage. It is only a modification 
of the ordinary Tetraspora- division, for it may already be 
observed in the true Palmellaceae. The only difference is 
that here the cell-walls separating the products of the division 
are only subsequently gelified, so that all the cells lie very 
close to each other, forming a very peculiar plate-like body. 
In Chlamydomonas variations are chiefly found in the cell- 
contents ; the chromatophore may be continuous or perforated, 
with or without one or several pyrenoids ; the latter are also 
variable in form in the different species. The species of 
Sphaerella , with their envelope remote from the body, are 
also closely related to Chlamydomonas ; in the earlier stage 3 
they cannot be distinguished from that genus, and the wall is 
close to the body. For this reason some young stages of 
1 Bull. Herb. Boiss., 1894, loc. cit. 
2 Goebel, Ueber Eudorina , Grundziige der Systematik, p. 41, Fig. 17. 
3 Cohn, Nova Acta Leopold XXII. Also, Chodat, Neige rouge du Col des 
Ecandies, Bull. Herb. Boiss., 1896. 
