176 Phillips . — The Development of the Cystocarp 
shoots gradually become transformed into the so-called ‘ pedi- 
cellate ’ cystocarps. These usually occur in considerable 
numbers along the lateral margins of the midribs, and have 
much the appearance, when mature, of aggregates of minute 
berries. By a careful comparison of a series of these struc- 
tures of varying degrees of maturity, the transformation of the 
young proliferations into the ripe cystocarps may be made 
out. With the aid only of such magnification as is afforded 
by a simple lens the following changes may be observed 
to occur. 
The young shoot in its primary condition is about 1 mm. 
long, and is lanceolate in outline, its width at its widest part 
being about twice that at its base (Fig. 2). It is perceptibly 
thicker along the mid-line, as if traversed by a rudimentary 
midrib. The first appearance of a cystocarp is a slight 
swelling at the mid-line on one of the surfaces. No dorsi- 
ventrality can be detected in these proliferations, and the 
swelling may arise on either surface. The circular base of 
this swelling gradually extends to the margins of the lamina, 
so that the outline is changed from lanceolate to ovate (Fig. 3). 
Widening still more, the outline might be described as rotund, 
were it not that a small triangular apical region of the 
originally lanceolate thallus persists as such (Fig. 4). In 
elevation the swelling rises so that the vertical diameter is 
soon as great as the horizontal diameter (Figs. 5, 7), and the 
swelling is roughly dome-shaped. With the growth of the 
cystocarp there becomes apparent near the summit of the dome 
a pore, the margins of which, later, somewhat protrude, trans- 
forming the dome into a broad-based urn. The lamina upon 
which the urn is situated does not remain flat, but, with the 
progress of growth, becomes somewhat depressed and convex 
below. The cystocarp, however, never becomes globular, the 
one-sidedness of the swelling and the existence of the 
triangular apical flap rendering such a term inappropriate. 
With the appearance of the cystocarp in the substance of the 
thallus its apical growth is arrested, and the urn-shaped 
swelling soon occupies almost the whole of the surface. When 
