THE PHILIPPINE 
Journal of Science 
Vol. XV 
DECEMBER, 1919 
No. 6 
CAMPBELLOSPHAERA, A NEW GENUS OF THE 
VOLVOCACEAE 
By Walter R. Shaw 
Of the Department of Botany, College of Liberal Arts, University of the 
Philippines, Manila 
TWO PLATES AND ONE TEXT FIGURE 
Mixed with several other species of Volvocaceae in living 
material collected at Pasig in July, 1914, there was a globular 
plant resembling in many respects Volvox carteri Stein. I 
regarded it as representing a new genus, and under the specific 
name carteri there accumulated in my notebook, in the course of 
months, a mass of data consisting largely of measurements and 
cell counts supposed to be descriptive of various stages in the 
life history of the plant. In November, 1916, when a written 
account of the new genus was nearly completed from the notes, 
a night session with a living specimen supposed to belong to the 
species revealed a difference in behavior inconsistent with the 
most distinctive character of the genus, thus making it evident 
that my description was a composite, embracing species of two 
genera. Consequently it has been my task to disentangle the 
descriptions of these species. 
The plant which is the subject of this paper has globular, 
biciliate protoplasts with no protoplasmic connections. It has 
gonidia which are differentiated from the somatogenic cells at 
an early stage in the development of the embryo, and they 
become so large, before dividing in their turn, that the species 
may be called megalogonidiate. But the distinctive character 
of the genus is a migration of the gonidia from the outside to 
the inside of the embryo. In the bowl stage of the embryo they 
168743 493 
