21,1 Shaw: Merrillosphaera 9] 
somatic wall are somewhat crowded and average about 9.5 bs 
between centers. Just outside of the flattened area the distance 
between cells is about 10 ». This, with an approximate mean 
diameter taken as 560 », gives 11,400 as the number of ceils. 
The protoplasts are somewhat farther apart in the anterior polar 
region. 
The somatic protoplasts are globose or oval, without con- 
necting filaments. They are about 5.4 » thick. Their distance 
from the outer membranous surface of the soma is about half 
a protoplastidar diameter or less. The outer surface appears 
quite even. The middle lamella between the protoplasts cannot 
be seen, nor is the inner limit of the cell membranes visible. 
Eight embryos are contained in the coenobium,? occupying 
positions in the coenobial cavity near the coenobium wall, four 
just ahead of the equatorial plane and the four others alternat- 
ing with them just back of that plane. The embryos are very 
darkly stained. They have developed into many-celled coenobia, 
in the walls of which gonidia may be seen embedded and protrud- 
ing. Six of the embryos can be seen to contain small numbers 
of reproductive cells. Two of them are not so clear. The one 
which is shown in Plate 1, fig. 2, is about 90 » in diameter; 
it has somatogenic cells of about 2.5 » width, and contains four 
cells of about 8 » diameter (which are not visible in the figure), 
grouped closely about what I take to be the site of the phialopore. 
It also contains eight cells about 17 » in diameter, obviously 
gonidia, distributed in the coenobium wall—five near the me- 
dian plane (two of which stand out clearly in the figure), one 
on the nearer side, and two on the farther side. 
A well-marked feature of the embryos is that their gonidia are 
embedded in the layer of somatic cells where they are formed. 
Being more cr less nearly isodiametric, and larger than the cells 
of the somatic layer, they protrude beyond the surface of the 
coenobium. 
ASEXUAL COTYPE SPECIMENS 
On the type slide are four other specimens of the same species, 
containing embryos in the same stage as those in the type speci- 
men, or slightly younger. With them are twelve asexual 
coenobia with gonidia and two sexual coenobia with young 
* The use of the term “coenobium” for the bodies of these organisms is 
not consistent with my view that they are properly to be regarded as 
individuals rather than as colonies. 
