20,5 Shaw: Janetosphaera and Volvox 483 
and extended to different degrees. So each protoplast is not 
inclosed in a little lamellar box of its own, as in Volvox globator, 
but occupies one of a layer of peripheral stalls each of which opens 
toward the interior of the coenobium into a segment of the 
central space that is shared by a number of protoplasts together. 
JANETOSPHAERA FROM CALIFORNIA 
My personal knowledge of Janetosphaera aurea is limited to 
that obtained from observations on two preparations in glyc- 
erine of material collected and mounted by myself at Stanford 
University, California, North 
America, in April, 1896. The 
material had been fixed and 
stained in picro-nigrosin and 
mounted under cover glasses that 
were then sealed to the slides 
by rings of Brunswick black. 
The staining had been very light, 
and the glycerine in which the 
specimens were mounted was 
slightly tinged with picric acid. 
After eighteen years the spec- 
imens, in 1914, as previously 
noted (Shaw, 719, p. 514), were 
in good condition; but the cement 
had become cracked and loosened 
to such an extent that it seemed 
advisable to remount the mate- 
rial. Before this was done some 
notes were taken that will serve 
as the source of the following 
descriptive data pertaining to 
Janetosphaera aurea found in 
Fig. 2. Janetosphaera aurea (Volvox aw California. 
_ reus). Diagram of cells and membranes The material in question con- 
ae a ee twenty-five mecaual 
coenobia on one slide and thirty- 
nine sexual and three asexual coenobia on the other. 
Measurements made of coenobia were: Asexual, 300 by 330 p 
and 320 by 380 ,»; sexual, 400 by 425 » and 640 by 700 xp. 
Estimates of the numbers of cells in these coenobia gave, in 
round numbers, respectively, 1,200, 1,800, 2,600, and 8,600 
These estimates were made by counting the cells in areas 90 p 
Square under a square-ruled eyepiece micrometer and making . 
