232 MOXOGEAPH OF THE LABOULBEXIACE^. 
It should be mentioned in this connection that in two genera (Dimorpliomjces and 
Dimeronijces) not only do the parietal cells lose their individuality as cells, but also 
the basal cells of the perithecium, the stalk-cell, and the secondary stalk-cell ; so that 
the cavity of the stalk-cell and that of the body of the peritheciura are continuous 
when the latter is fully mature. In these cases, as in many other genera, the cavities 
of the lower wall-cells of the peritheciura are gradually obliterated, as the spore mass 
increases ; the terminal and subterminal wall-cells often being the only ones, in old 
individuals, in which the cell cavity can be made out. 
Before leaving the subject of the derivation of the two series of cells which consti- 
■ 
tute the outer and inner portions of the body of the perithecium proper, and of their 
relation to the cells below, it must be confessed that my first impression concerning 
the origin of the inner series was that they arose from the primary wall-cells (Plate I, 
fjg. lo, n), through the formation of longitudinal tangential septa, it being a matter of 
great difficulty to make out their exact position and relations at the earliest period of 
tlieir development; and it was not till the protoplasmic connectionsdof both the outer 
\ 
observed 
of Laboulbenia the 
cells of which had been separated by treatment with potash, that the true condition 
of things suggested itself. These connections, in so far as they have been absolutely 
seen in given instances, are represented in figs. 16 to 18 of Plate II, which should 
be compared carefully with the account above given of the successive origin of the 
stalk-cell, the basal cells, and the wall-cells : the lett 
th 
corresponding in general to that of the figures above cited on Plates I and III. In 
figs. 16-17 (Plate II), the parietal cells, as well as the inferior supporting cell below 
the ascogenic cells, had been destroyed, so that the protoplasmic connection with 
these cells had also disappeared; but in fig. 18, which represents a young individual, 
some of them were distinctly visible, and it was apparent that the inferior supporting 
cell {i s), and the two anterior basal cells (^) and {d), were definitely connected with 
the secondary stalk-cell (h), and that the two visible parietal cells (pc) were similarly 
connected with the two anterior basal cells. A second preparation showed with equal 
distmctness that the posterior basal cell (o^) was similarly connected with one of the 
parietal cells. It was, however, impossible to determine which of the two anterior 
basal cells gave rise to two and which to one parietal cell ; yet it is safe to assume that 
the same cell {d) which (fig. 17) gives origin to two wall-cells, is also connected with two 
parietal cells. In the preparation, as will be seen (fig. 18), three connections were vis- 
ible from this cell : one of which was evidently with a parietal cell, another with the 
wall-cellf/), the thu-d running beneath and connecting on the opposite side either with 
) 
^ 
