Cavers . — On the Structure and 
1 1 6 
4. The antheridia are usually sunk in separate cavities, but in some 
cases a single cavity contains two antheridia closely joined together and 
strongly flattened along the surface of contact. 
5. The antherozoids are explosively ejected from the openings of 
the flask-shaped antheridial cavities ; the essential factor in the process 
is the absorption of water by the mucilaginous antherozoid mother-cells 
and those forming the antheridium-wall, leading to considerable pressure, 
which is relieved by the discharge of the antheridial contents in the upward 
direction, that of least resistance. The antherozoids are larger than in 
other Marchantiaceae ; each consists of at least two complete turns of 
a spiral, and the thicker posterior end often shows a vesicle, the remains 
of the mother-cell. 
6 . The archegonial receptacle, like the antheridial, represents a branch- 
system, but each of the (5-9) growing-points only produces a single 
archegonium. The stalk of the receptacle remains very short until 
after the sporogonia are ripe, and immediately before the dehiscence 
of the capsules it suddenly attains a length of 3-6 cm. ; this elongation 
is due solely to growth in length of cells already present, the starch 
contained in the cells of the stalk being used up during the growth in 
length of the latter. 
7. In the development of the archegonium, the cover-cell becomes 
immediately divided by intersecting vertical walls and takes no part in 
the growth in length of the archegonium, as asserted by Gayet to be the 
case in Marchantia , Preissia, and other Hepaticae. 
8. The young sporogonium usually shows an octant-stage, and does 
not grow by means of an apical cell, as stated by Hofmeister. 
9. The large, green, thin-walled spores begin to germinate within 
the capsule, each forming an ovoid cell-mass. Beyond the occasional 
formation of short rhizoids no growth takes place in darkness. The spores 
are not adapted to resist desiccation. 
10. The relatively short elaters are frequently branched ; the branching 
takes place at the time when the spore-tetrads become separated and 
loosened within the capsule. 
11. The capsule opens by throwing off a thickened discoid apical 
cap, the rest of the wall then becoming split longitudinally into 4-8 valves. 
12. Fegatella may be regarded as the lowest member of the 
Marchantioideae-Compositae, with which it agrees in the structure and 
development of the thallus, male receptacle, and sporogonium. In the 
organization of the female receptacle Fegatella approaches the Marchanti- 
oideae-Operculatae. It appears, therefore, to occupy an intermediate 
position between the two highest series of the Marchantiaceae. 
