10 CONNECTICUT GEOL. AND NAT. HIST. suRvEY. [Bull. 
borne on a short stalk. The sac is bounded on the outside by 
a wall composed of a single layer of sterile cells, and the 
whole interior is occupied by a compact mass of fertile cells, 
each one of which gives rise to a single male cell, or sperm. 
When the antheridium is mature, it absorbs water and bursts 
its wall, allowing the sperms to escape and swim away. Each 
sperm consists of a slender body, and swims by means of two 
long and delicate cilia attached at one end. 
The archegonium may also be stalkless or borne on a short 
stalk, but is more slender than the antheridium. The single 
female cell, or egg, is developed in the swollen basal portion 
which is called the venter, and this is tipped. with a somewhat 
longer cylindrical portion called the neck. Both venter and 
neck are bounded on the outside by a wall composed of 
sterile cells. The egg represents the lowest of a row of cells 
enclosed by this wall, the remaining cells, which fill the neck 
and a portion of the venter as well, being known as canal cells. 
When the mature archegonium absorbs water, the neck opens 
at the tip, and the canal cells break down into a mass of 
slime, some of which escapes through the opening. In this 
way a free canal is formed which leads from the outside into 
the venter, and at the base of this canal the egg becomes 
rounded off. The sperms, attracted by the protoplasmic slime 
exuding from the archegonium, swim toward it, and one of 
them makes its way down the canal, uniting with the egg 
and thus completing the process of fertilization. 
As soon as this has been accomplished, the fertilized egg, 
without escaping from the archegonium, begins at once to 
develop into the sporophyte, which remains in contact with 
the gametophyte during its entire life, without being organ- 
ically connected with it. The chief function of the sporophyte 
is to develop asexual spores, but some of its cells invariably 
remain sterile and perform functions not connected with 
reproduction. In the more primitive Bryophytes it is practi- 
cally destitute of chlorophyll, and is therefore wholly dependent 
upon the gametophyte for food, living as a parasite upon it. 
In the higher forms it develops green cells, capable of per- 
forming photosynthesis, and probably derives nothing from the 
gametophyte except solutions of inorganic substances. In 
such cases the parasitism is only partial. The portion of the 
