21,1 Shaw: Merrillosphaera 97 
A free male coenobium (specimen 10) in the same collection as 
the type specimen is shown in Plate 1, fig. 7. After it was photo- 
graphed the specimen became crushed between two glass rodlets 
so that the antheridia cannot be counted. The somatic proto- 
plasts are about 4.5 to 5 » wide and spaced about 12 p. The 
diameter of the coenobium being about 253 ,», the number of the 
somatic cells is about 1,600. The reproductive bodies are all 
sperm platelets that are more or less cupped and measure 14 
to 19 » in diameter. They are too darkly stained to admit of 
' counting the sperms. The specimen shows plainly the cilia of 
the somatic cells and of the sperms. Each sperm platelet is 
contained in a cavity about 46 » in diameter. 
Two free male coenobia that appear to belong to the same 
species are in company with the specimen shown in Plate 1, 
fig. 5. They are very similar to the males within this mother. 
These two specimens (Nos. 11 and 12) are 295 by 316 » and 316 
by 324 » in diameter and have about 1,700 and 1,800 cells. The 
Somatic protoplasts are about 7 » in diameter and measure about 
23 » wide. The antheridia number about 200 in each coenobium 
and are distributed without leaving a well-marked vegetative 
pole. They are mostly in the 16-celled stage of division, though 
some have divided only once or twice. On the same slide with 
them there is a larger male coenobium that I take to be of another 
species. It is larger, 390 by 418 », and has smaller cells, 6 », 
that are more numerous, about 2,900. The antheridia also are 
smaller, 18 », and more numerous, about 640. This coenobium 
has no vegetative pole marked by absence of reproductive cells, 
but the posterior half is narrowed slightly as is commonly the 
case in Merrillosphaera africana. 
FORMS OF ASEXUAL COENOBIA 
The photomicrographs used for illustrating this paper have 
been selected from about one hundred fifty that were made to 
serve as an aid in the task of separating the five or six species 
of larger Volvocaceae that occurred in various mixtures in the 
collections made in the neighborhood of Manila. This was done 
at a time when the number of species and genera was not known. 
The selection of material was based largely on suitability of the 
specimens for photography. A result of thus working simulta- 
neously with a number of species is that no one species was 
followed as far through its range of variation as might have 
been done had it been studied alone. Since the photographed 
187663-——7 
