1913) YAMANOUCHI—HYDRODICTYON AFRICANUM 79 
so-called pyrenoid, spherical in form and consisting of a denser 
central portion surrounded by the body of the plastid (fig. 4). 
The formation of starch grains by the direct fragmentation of 
the pyrenoid as described by TimBERLAKE does not occur in this 
new form. The method of starch formation is as follows. Ina part 
of the body of the plastid near its margin a starch grain is formed 
either by secretion, as MEYER believes, or in some other way. 
The starch grain grows and finally reaches a size equal to that 
of the pyrenoid. The starch thus formed is more abundant toward 
the plasma membrane (fig. 5). 
|, ED Fo 
Fic. 5.—Stages showing the formation Fic. 6.—Gametes: a, part of a section 
of starch grains by plastids.—X 1500. showing the gametes lying near the cell 
wall, X1200; b, a single gamete, X 1500. 
-The gamete formation was not observed in living cells, but in 
fixed material many cases of cells were observed in which a majority 
of the spores had escaped, still leaving a number of spores within. 
Whether the spores are zoospores or gametes was not ascertained, 
but judging from the condition in H.. reticulatum they should be 
gametes. 
Hydrodictyon africanum Yamonouchi, sp. nov.—Young net a about 60 
coenobia; when old, coenobia becoming solitary by breaking apart on account 
of their great turgidity and loose connections; coenobia deep green, but yellow 
with age, spherical or oblong, and finally attaining an enormous size, as large 
as 1.5 cm.; the coenobia live a long time in the solitary condition. 
TYPE LocaLity.—Valkenberg Vlei, near Cape Town, South Africa. 
University oF CHICAGO 
