MOSSES AND LIVERWORTS 103 
among the alge is found in the stoneworts (Characee), 
but the differences in the vegetative parts between these 
and the Hepatice are too great to admit of the idea of 
any but the remotest 
relationship existing 
between the two, and 
at present it must be 
admitted that the 
gulf between Alge 
and Archegoniates is 
a very deep one. 
The antheridium is 
not so different from 
Fic. 26.—A, longitudinal section of the 
that of some alge, but 
is much more com- 
plicated than in any 
but the Characeze. In 
the Archegoniates it 
has the form of a 
capsule (Fig. 26, C), 
archegonium of a liverwort (Targionia), 
showing the central row of cells; B, a 
similar section of the ripe archegonium 
of Riccia; the cells of the axial row are 
disorganized and the egg, 9, lies free in 
the enlarged venter of the archegonium ; 
C, longitudinal section of the antherid- 
ium of Riccia, showing the mass of sperm- 
cells surrounded by a single layer of 
peripheral cells; D, a free spermatozoid 
of Fimbriaria Californica, 
which in the lower 
forms is usually stalked. The central part is divided 
into many small cells, in each of which is developed 
a spermatozoid. The latter is very much like those of 
most alge, and like them is provided with cilia (Fig. 
26, D). 
Throughout the whole group of the Archegoniates 
water is necessary for the opening of both archegonium 
and antheridium, the water swelling up the mucilagi- 
nous cell-walls of the interior of the organs, thus forcing 
them open. The liberated spermatozoids then swim to 
the open archegonium, which in the mean time has dis- 
