Biology of Fegatella conica. 103 
of the thallus (Figs. 29, 30). After fertilization of one or more of the 
archegonia, the development of the sporogonia begins and is continued 
during the rest of the year. In the following spring, the stalk of the 
receptacle, which has up to this time remained very short, begins to grow 
in length and in a few days reaches a height of from 3 to 6 cm., carrying up 
the receptacle (PI. VII, Fig. 33). Then the capsules open and the spores 
are set free. 
The earliest stages in the development of the female receptacle are 
a little difficult to follow, but it would appear that here, as in the case of 
the male receptacle, the growing-point undergoes repeated branching. 
Leitgeb (1881, p. 94) leaves the question open, though bringing forward 
strong theoretical grounds for regarding the carpocephalum as a branch- 
system. The examination of numerous series of sections through young 
receptacles has convinced the present writer that branching does take 
place in the growing-point, repeated dichotomy giving rise typically to 
eight growing-points, which are separated by rounded sterile lobes, exactly 
as in the branching of the thallus. The carpocephalum of Reboitlia hemi- 
spherica does not differ greatly in external form from that of Fegatella , but 
microtome-sections of the former show clearly the single growing-point 
lying below and in front of the receptacle. This is not the case in Fegatella , 
and there can be no doubt that here the apex of the fertile branch is used 
up in the formation of the whole receptacle, not merely of the stalk, and 
that the receptacle itself represents a modified branch-system, essentially 
homologous with the male receptacle. 
The young receptacle first appears as a dome-like prominence, formed 
by active growth of the dorsal segments of the initial cells (PI. VII, Fig. 38). 
These cells undergo repeated vertical divisions, so that the tissue of the 
young receptacle presents in horizontal sections a nearly circular outline, 
the cells being arranged in radiating rows (PI. VII, Fig. 42). The next 
stage shows a slightly rounded lobe occupying the anterior end of the re- 
ceptacle and recalling the ‘ middle lobe ’ seen in ordinary apical branching 
of the thallus. The cells composing this anterior lobe grow and divide 
very slowly, but those occupying the slight depression on either side of it 
divide actively, especially by vertical walls, and obviously constitute two 
distinct growing-points (PI. VII, Fig. 43). Next, each of these growing- 
points becomes broadened, and in its centre there appears a secondary lobe 
(PI. VII, Fig. 44). The receptacle now shows four growing-points, but each 
of these rapidly grows in breadth, and its central cells grow out to form 
a tertiary middle lobe (PI. VII, Fig. 45). In most cases, the branching of 
the young receptacle does not proceed further than this, but sometimes one 
or both of the two anterior growing-points again becomes branched, so that 
the receptacle may show nine or ten growing-points instead of the eight 
which are normally found. On the other hand, one or more of the divisions 
