7 
of Splachnum luteum . 
apophysis by the chloroplastids, each chloroplastid containing 
a number of separate starch-grains. When the apophysis is 
quite young, at this time being green, immediately on its 
beginning to become umbrella-shaped, and before the spores 
ripen, the starch begins to be formed. At a later stage the 
starch disappears, the starch-forming plastids, which before 
were large and well-formed, degenerate into small and com- 
paratively inconspicuous bodies, the starch apparently being 
used up in the formation of spores. In all probability there 
is at this period a formation of xanthophyll, which would 
account for the yellow colour of the apophysis in the mature 
condition of the sporangium, and hence the name of the 
species. 
That the apophysis performs the functions of a leaf, and is 
therefore analogous with the leaves of vascular plants, I think 
there can now be no doubt. And as this structure is a 
development of the sporophyte, the possibility of its being 
also homologous , either directly or indirectly, suggests itself. 
I am myself inclined to believe that the two are homologous ; 
but to give a full discussion of that question would be beyond 
the scope of the present communication. 
The structure of the spore-capsule is quite typical : it is 
covered by a dark reddish-brown epidermis, which is cuticu- 
larised. The outer walls of the epidermal cells are rather 
thin, but the radial and anticlinal walls are thickened in a 
peculiar and characteristic way (Fig. 19): it will be observed 
that on the thickened side-walls of the epidermis there are 
large pits of varying form, as seen when looking on to the 
walls in the plane of the section ; at the same time the walls 
which are at right angles show thickenings of an elliptical 
or cordate shape : similar thickenings occur in other species 
of Splachnum \ Beneath the epidermis there are two or 
three layers of cortical cells, and then the large intercellular 
space (I) in Figs. 9 and 10, characteristic of the Moss-capsule. 
The columella has the same structure as I described in a 
1 VnilTemin, Sur les homologies des Mousses; Nancy, 1886. 
