21,2 Shaw: Copelandosphaera 225 
bodies of water, Nebraska (J. H. Powers, 1904?) ; Washington 
State (Elda R. Walker, 1904?) ; a shallow pond, near Rocheport, 
Missouri (R. H. Wolcott, 1904); and probably New Orleans, 
Louisiana (E. Foster, 1904?). 
THE RELATIONSHIPS OF COPELANDOSPHAERA 
It has been pointed out by Crow (18) that Stephanosphaera 
and Volvox bear, in the characters of their cell membranes, 
cell connections, contractile vacuoles, and chloroplasts, a strong 
resemblance to the unicellular genus Sphaerella, whereas the 
other multicellular genera of the Volvocaceae resemble in these 
characters the unicellular genus Chlamydomonas. According 
to Crow, the relationships of these genera would be best ex- 
pressed by grouping them into two families, the Sphaerellaceae 
and the Chlamydomonadaceae, that present two lines of evolution 
on parallel lines. Such an arrangement would bring into the 
Chlamydomonadaceae in this sense Gonium, Pandorina, Stepha- 
noon, and Eudorina of lower organization, Pleodorina and Bessey- 
osphaera of intermediate organization, and Copelandosphaera, 
Merrillosphaera, and Campbellosphaera of higher organization. 
While such a disposition may represent the course of phylogeny, 
nevertheless the subfamily Volvoceae, embracing all the mul- 
ticellular Volvocaceae, will be useful for practical purposes. 
A key to the genera and species of Volvoceae, which is here- 
with presented, will serve to show the position of Copelando- 
sphaera among its relatives. 
The nearest relative to Copelandosphaexa on the side of lower 
organization is Besseyosphaera, which has its gonidia not dif- 
ferentiated until after the birth of the coenobia. Although 
the sexual reproduction of the latter genus is not known, we 
can, without difficulty, picture it as something intermediate 
between that of Copelandosphaera and that of Pleodorina ecali- 
fornica as described by Chatton (’11), and not greatly dif- 
ferent from either. 
The nearest relatives on the side of higher organization are 
the species of Merrillosphaera. The relationship is so close 
that some people may prefer to reduce them all to one genus. 
This would be undesirable at the present time, for it is almost 
certainly true that the assumption that all of Volvox is com- 
prised in two or at most three species was, until the time of 
Powers’s work, a deterrent to the proper study of such forms 
of this group as were found. In identifying them, if the form 
in hand had rounded protoplasts it was set down as Volvox 
aureus, and if no protoplasmic connections could be seen it was 
