214 The Philippine Journal of Science 1922 
MATURING SEXUAL COENOBIA 
We will pass to a consideration of sexual coenobia that are 
approaching maturity and describe the one* that is represented 
by Plate 1, figs. 1 to 3. This and the two sexual coenobia 
that are shown on the next plate are in the lot of glycerine 
preparations that were made from the Pond J material from 
Pasay, October 13, 1914. 
Specimen 12.—Plate 1, fig. 1, shows a sexual coenobium with 
antheridia very nearly mature. This specimen is a slightly 
ovoid coenobium about 610 by 660 ». The number of cells 
forming the coenobium was estimated to be about 17,600. The 
protoplasts of the cells are ovoid and measure about 6 by 7 yu 
in the front and 4 by 5 » in the middle and back of the coeno- 
bium. .The distance between the protoplasts is greatest in the 
front and grades to the minimum at the back. The oogonidia 
when counted in a camera lucida sketch were found to be 127. 
They are distributed in about three-fourths of the length of 
the coenobium and are slightly more crowded in the hindmost 
quarter than elsewhere. They are globular and measure about 
28 » in diameter. Their outer sides are only about 10* below 
the outside surface of the coenobium. The antheridia that can 
be seen are ten, and they are not all grouped in pairs like the 
four shown in the photograph. Each antheridium consists 
of a platelet about 37 » wide and 10 » thick, slightly dished, con- 
sisting of about 256 closely packed sperms. The vacant spaces 
in the coenobium wall over the two antheridia that can best be 
seen are large enough to have seven protoplasts around them. 
They are, if different, larger than the spaces above the oogonidia, 
most of which seem to have not much more than six protoplasts 
around them. 
Specimen 13.—Plate 2, fig. 4, shows a nearly mature sexual 
coenobium on a smaller scale. The picture was taken with 
a focus below the middle of the specimen, and the oogonidia 
that show most plainly are those of the farther side. The coeno- 
bium measures 760 by 840 yn, the spacing of the cells is about 
10.7 », and the number of cells about 19,600. Few antheridial 
sites can be distinguished in the coenobium wall. The oogo- 
“This one had been selected, at the time when the figures were made up 
into plates, to serve as the type of the species, but it is now thought that 
the characters of the genus are better shown by mature asexual coenobia 
with their contained daughters. 
*This number was obtained by finding that the diameter of a platelet 
is about equal to 18 sperms in a straight row. 
