20, 6 Shaw: Janetosphaera and Volvox 485 
outer wall about 79 » in diameter. The spore walls are smooth, 
and the zygote protoplasts are eccentric within them. These 
are immature spores. 
Mature oospores have, in addition to the spherical smooth 
outer wall, a much smaller spherical smooth inner wall that is 
eccentric and in contact with the outer wall on one side. The 
specimens are now under slight pressure of the cover glass and 
the spores may be slightly flattened and widened. In one of 
the mature oospores the outer wall measures 75 » in diameter, 
the inner wall 62 », and the protoplast 57 yp. 
VOLVOX Linnaeus 
(Volvocaceae, Volvoceae) 
Type species, Volvox globator (L.) Ehrenberg. 
Characters which serve to distinguish the species properly 
included in this genus from species that should have places in 
other genera are embraced in the following diagnosis: 
Globose, free-swimming bodies, consisting of very numerous 
biciliate cells forming a peripheral layer; the protoplasts more 
or less star-shaped and covered with thickened walls through 
which neighboring protoplasts are connected by stout protoplas- 
mic processes; each cell containing a green chloroplast. The 
cell membrane typically with a firmer lamella cutting off the cell 
from the interior of the body. 
The descriptive diagnosis of the type species as given by 
Klein has been transcribed in the following paragraphs. 
VOLVOX GLOBATOR (L.) Ehrenberg (fide Klein, ’90, pp. 82-84). 
Volvox stellatus Ehrenberg 1831. 
Volvox monoicus Cohn 1875. 
Coenobia usually somewhat elongated, seldom exactly spher- 
ical; diameter mostly 600 to 800 », occasionally ranging from 
400 to 1,200 x. 
Somatic cells mostly about 10,000; ranging from 1,500 to 
22,000. 
Somatic protoplasts 2 to 7.5 », usually 3 to 5 », irregularly 
star- or amoeba-shaped, mostly somewhat crowded; chloroplast 
extending into the cytoplasmic processes, which are almost 
always simple and usually, even when the chloroplast processes 
are withdrawn, considerably thicker than the cilia. 
Gonidia of the same form (amoeba-shaped) as the somatic 
cells, becoming 15 to 18 » in diameter before the first division, 
connected with the neighboring somatic cells only by single pro- 
