SS RR Ee le a Ree ene a at eet ee ED eee eg ee oe SP aks ae pig. hee 
ere Pou ht ie 
foie 
Bee ean - 
1913] TRANSEAU—GLOEOTAENIUM 71 
spore. I have found a number of cases where the divisions have 
taken place before the cell left the family, and before the heavy 
gelatinous outer covering was secreted (figs. 18 and 23). But it is 
probable that in most instances this division takes place after the 
resting period (fig. 2), for most of the aplanospores which I have 
examined showed no division and 1-celled mature individuals are 
comparatively rare. 
That the propagative cells from 2-celled families do not neces- 
sarily form 2-celled families is shown in fig. 18, in which one of the 
cells has divided twice, the other but once. The development of 
the bands may be clearly understood from fig. 4. After germina- 
tion (fig. 3) begins, the cells assume a more and more spherical 
form. Accompanying this process is the gradual separation of 
the cells and the secretion of the gelatinous layer from the adjacent 
cell walls. 
My experience with Gloeotaenium both in the field and in cul- 
tures is thus far against the probability of zoospore production. 
The extreme localization of the collecting places in the ponds; the 
fact that it is most abundant on the bottom, and is brought to the 
surface only through the rising of other algae; and the fact that in 
the laboratory aquaria it is found only on the bottom, all point to the 
absence of swimming spores during the period I have had the plant 
under observation. 
In the light of the above observations I should put the plant 
among the Scenedesmaceae near the genus Oocystis. The present 
description of the genus will require modification as follows: 
Cells globose or variously flattened, solitary or united in families 
of 2, 4, or 8 cells, with wide and distinctly lamellate cell walls; the 
mother cell wall is frequently ornamented with folds and gelati- 
nous disks opposite the cells; a dark-colored gelatinous layer 
usually extends between the cells of a family; chromatophore 
globose, with or without a pyrenoid. Reproduction by aplano- 
spores and daughter cells. 
The writer is under obligations to Mr. FRANK S. CoLLins and 
Professor WILLIAM TRELEASE for the loan of literature. 
CHARLESTON, ILL. 
