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Transactions of the Society. 
tlieca. While the spores are developing, the ventral part of the 
archegone continues to grow and enlarges into the calyptra, which is 
torn off and incloses the young sporogone, the basal part being left 
behind as the vaginula inclosing the seta. The spores originate in 
fours, each mother-cell dividing into four, and in all respects they 
resemble the spores of ferns. 
The Sphagna differ from the true Mosses by the spongy cortical 
layers of the trunk, the branches collected in fascicles, the very curious 
and beautiful structure of their leaves, and the antheridia being 
subglobose in form, with very fine branched paraphyses and grouped 
as an amentum or catkin on an abbreviated branch. The spores 
of Sphagnum, if germinating in water, form a slender branched 
protonema, but if their development takes place on the ground, a 
lobed prothallus is formed resembling a plant of Blasia, and from the 
edges of the lobes young plants bud off. 
The Hepaticae or Liver-mosses vary much more among themselves 
than the Mosses, the majority of them are branched and leafy, but a 
considerable number retain permanently the thallose condition, the 
proembryo continuing to grow and branch out, without any new 
leaf- bearing generation. In the foliose Jungermannieae the antheridia 
are globose as in Sphagnum, and, as in that genus, are often arranged 
on a short branch m amentiform clusters, or they may be solitary and 
axillar. In the thallose forms the sexual organs are on the upper 
surface, the ventral surface bearing scales and rhizoids, and the 
product of germination in the Hepaticae resembles closely that of ferns. 
In Pellia, for instance, the terminal cell of the spore elongates to 
form a root, the others multiply and expand into the flat horizontal 
thalliform trunk. In the leafy Hepaticae three modes of development 
of the spore have been observed; in the group Frullanieae a flat 
round disc is formed, and on the margin of this a bud is developed 
which grows into a leafy stem ; in Jungermannieae with round entire 
leaves, as Plagiochila, it is a thickened cylindric cellular mass, 
which is at once transformed at the apex into the trunk ; in Junger- 
mannieae with cleft leaves, e. g. Diplophyllum, it is a slender branched 
thread of protonema, which produces a naked body from which the 
trunk is formed. 
In Marchantia the frond sends out a branch which grows a certain 
height and is then transformed at the summit into a disc, bearing 
beneath many female inflorescences ; this has been termed by Lind- 
berg a Carpocephalum, and its peduncle a Cephalopodium. On the 
posterior part of this peduncle one or two deep furrows contain 
numerous radical cells, having in the interior claviform thickenings, 
and which has on the anterior part the epidermal orifices which serve 
as canals to small air-cavities, lined in the interior with rows of 
opuntiform cells. The common disc is more or less conical with four 
to ten rays, beneath and alternating with which are the widely bila- 
biate and fringed perichaetia inclosing the sporogones. The male 
