Cavers : Xotes on Yorkshire Bryophytes. 249 



has a twisted body, showing' usually two turns, and bear- 

 ing at one end a couple of very fine threads or cilia, each 

 about twice as long- as the body itself. At the other end of the 

 body there is usually attached a small vesicle, containing a few 

 small starch-grains. This vesicle, which represents the residue 

 of the mother-cell that produced the antherozoid, often becomes 

 detached during the swimming movements of the male cell. 

 The mature archegonium has the usual form of a flask with 

 a slightly dilated lower part and a long neck. The neck 

 contains a row of cells (canal-cells), and the dilated part (venter) 

 contains the egg-cell. When water is absorbed by the arche- 

 gonium, the neck-cells (which have become mucilaginous) are 

 dissolved and a string of gummy liquid comes out at the end of 

 the neck, which is now accessible to the swarming male cells. 

 One of the latter eventually fuses with the egg-cell. 



Sporogonium. — The fertilised egg-cell divides first by a 

 transverse wall, and then vertical divisions occur, until the 

 embryo consists of eight cells (octant stage). The four upper 

 cells give rise to the capsule or spore-producing part of the 

 sporogonium or fruit, the four lower cells grow and multiply 

 and form a small spherical mass of cells, the foot. Between 

 the large spherical capsule of the ripe sporogonium and the foot 

 there is a very short neck or seta (Fig. 5, A.). The venter of 

 the archegonium growls and keeps pace with the increase in size 

 of the capsule, forming the calyptra, at the summit of which 

 one sees the neck of the archegonium, now withered and tinged 

 with red. 



Capsule. — At a fairly early stag-e in the growth of the 

 sporogonium the tissue of the capsule becomes differentiated 

 into an outer layer of cells which will form the capsule-wall, and 

 an inner mass of cells w^hich will ultimately produce the spores 

 and elaters. The capsule wall is a single cell in thickness, 

 except at the summit of the capsule, where there is a lens- 

 shaped cap of cells (Fig. 6, B., C). This cap is 3 or 4 cells 

 thick in the centre, thinning out to a single layer at the margin. 

 In the lower part of the ripe capsule the cells forming the wall 

 are entirely without ring-like or other localised thickenings of 

 the cell-walls, but towards the apex of the capsule the cells 

 have their radial walls thickened, especially at the angles 

 between adjacent cells. 



The ripe capsule eventually enlarges, breaking through the 

 calyptra and emerging slightly from the lower surface of the 

 receptacle (Fig. i, E., F.). Then the apical portion of 



1904 Aug-ust I. 



