276 BOTANICAL GAZETTE | ocroweR 
of development as that of fig. 7 is given under the same magni- 
fication. The medullary bundle J/ is nearly circular in cross- 
section. 
A developmental change now sets in through which the out- 
line of the medullary portion becomes lobed. These lobes 
alternate in position with the later formed columns of the recep 
taculum and extend longitudinally from near the base of the 
egg almost to the apex of its medullary bundle. The four such 
lobes usually formed in C. colunnatus are shown in the cross-sec- 
tion of an egg in this stage (G, G, fig. 4). Fig. 4 is drawn with 
the same magnification as figs. r and 2, the diameter of the egg 
having become only slightly greater. Many eggs of about the 
same diameter as these were sectioned and examined in order 
to find intermediate stages between those of figs. 7 and 2 and 
jig. 4, which would show the mode of differentiation of the med- 
ullary lobes G, G. It seems probable that their differentiation 
occupies only a short interval of time, for only one egg in Oe 
intermediate stage was found. It is shown in cross-section in 
Jig. 3, and under the same magnification used in the other cases- 
In this stage ( fig. 3) the medullary and cortical layeis are less 
sharply distinct from each other than in the earlier or later 
stages. At three points, perhaps four, hyphae seem to be invad- 
ing the cortical region of fig. 2 and forming masses (G). These 
masses are the rudiments of the gelatinous layer of the volva of 
later stages. Only three such lobes can be made out with cer 
tainty in this stage, while four are present in the more advanced 
stage of fig. 4. The absence of the fourth may indicate that the 
differentiation of all four lobes does not begin at exactly the 
same time; but it seems more probable, however, that this is a 
early stage of a Clathrus having three columns for its receP oe 
lum. In such a plant oniy three gelatinous masses are acd 
in the gelatinous layer of the volva. Specimens having ae 
three columns did occasionally occur in this material. 
The rudiments (G, G, G, fig. 3) of the gelatinou 
volva are most intimately connected with the central me 
mass and must undoubtedly be regarded as belonging ns 
s layer of the | 4 
dullary — 
the 
