r9r3] TRANSEAU—GLOEOTAENIUM 69 
globose, sometimes flattened on the inner side, and sometimes on 
the outer. Between the two cells there is usually a gray, brown, 
or black band (figs. 8 and 9) composed of a more or less tough 
granular gelatinous secretion. This substance is at first colorless 
(fig. 4) and darkens with age. The color is partly due to total 
refraction and partly to a pigment. When the band is absent the 
caps also are wanting (fig. 10), but the band may be present with- 
out the caps. The mother cell wall is retained until late maturity, 
that is, until a short time (probably one or two weeks) before the 
breaking up of the family. In some cases this implies an existence 
during three or four months, and for those most favorably situated 
for development about a month. 
My earliest outdoor record for the late maturity and aplano- 
spore stage (figs. 17 and 18) is July 21. The disappearance of the 
mother wall is probably coincident with a rather rapid increase in 
the diameter of the vegetative cells from an average of 20 to an 
average of 30. ‘The cells remain attached to the band for a short 
period, but finally break away from this by their continued enlarge- 
ment also. This last separation is clearly not due to the gelatini- 
zation of either cell wall or the band as stated by most authors. 
This is shown by the fact that after separation the band usually 
exhibits a ragged transparent edge, or occasionally there remains 
attached to it a thin wall from which the cell has escaped by tearing 
along the line of juncture with the bands. At the time of separation 
the cells may be thick or thin-walled, and may have divided inter- 
nally (fig. 18). The thin-walled aplanospores germinate very soon 
by enlarging and dividing. The thick-walled aplanospores secrete 
a further gelatinous covering (fig. 1) and go through a rest period. 
Those cells which have already divided before separation may 
continue development (in the summer) or become thick-walled, 
secrete a gelatinous covering, and go into a rest period (in late 
autumn). 
The 4-celled families are of two distinct types: (1) those having 
the cells in the same plane; (2) those in which the cells have a 
tetrahedral arrangement. In both the vegetative cells are similar 
to those of the 2-celled families. The 4-celled families with the 
cells in one plane (figs. 12.and 13) are about as abundant as the 
