NE MR. HENFREY ON THE DEVELOPMENT 
its cavity. The same takes place upwards and downwards, and thus the antheridium, 
when examined in this state, seems to consist merely of one large cell (figs. 21, 22 & 26), 
with rather thick walls consisting of a double membrane (figs. 24, 25). j 
While in this expanded condition the entire structure increases in size, and the contents 
of the central cell become more granular. After a time faint lines can be detected run- 
ning through the protoplasm (fig. 21), and these soon display themselves more clearly as 
the boundaries of square isolated masses of the protoplasm (figs. 22 & 25), the nascent 
sperm-cells. ‘Around each of the little masses thus isolated a membrane is formed. -It 
was impossible to ascertain whether the parent-cell was first divided into a number of 
square partitions, by cross walls, thus producing * special parent-cells," for the sperm-cells, 
like those formed in the development of pollen-grains, the original partitions subsequently 
becoming dissolved to set free the cells thus originally connected together; or, whether 
the protoplasm was simply entirely broken up into a number of isolated portions, each of 
which secreted a membrane and thus formed a free cell; but I incline to believe that the 
latter was the fact, and that the same oceurs in the completely similar case of the produc- 
tion of a number of closely packed endosperm-cells, in the embryo-sac of many Phanero- 
gamia, as in the Cruciferæ and Scrophulariaceæ*, However this may be, the result is the. 
production of a large number of free cellules, filled with mucilaginous protoplasm (figs. 26, 
34), of a light yellowish colour, becoming gradually more and more granular. As these 
cellules, at first squarish, enlarge, they become spherical, and by their expansion distend 
the parent-cell and disguise the existence of the annular coll surrounding it. Their num- 
ber, in well-developed antheridia, seems to be between thirty and forty, probably never 
exceeding the latter number. ! 
The free cellules, the sperm-cells, become more and more opake and granular, and after 
o vn spisal lines may be detected in them, while still within the parent-cell in the 
antheridium (figs. 35 & 36). At this time the antheridia may be burst very easily by pres- 
sure (fig. 36), ani the sperm-cells which escape can be observed in all stages of develop- 
ment, until a spiral fibre can be clearly seen, coiled up in the interior. Specimens lying 
in water, under the microscope, now frequently exhibit a movement of the contents of the 
sperm-cells, they swell up, and the spiral lines are seen to change their position. Very 
often the bursting of the sperm-cells takes place within the antheridium, and the sperma- 
en entire from the antheridium. This occurs by the splitting of the line of junction 
E e lenticular cell crossing the antheridium with the lateral cell, at first at one side and 
s usually all round, but sometimes it remains attached by a small portion (fig. 48). 
completely opened. 
A . . . ; 
s the opening of the lid gives a vent to the contents of the distended central cell, the 
tub TERI : 
Pen baee cit E exerts a pressure inwards by striving to regain its original form, 
| "perm-cells are discharged, the side-walls of the central cell come back into 
* T have observed it in Lathrea Squamaria most distinctly. 
