209 
Up to this time’ the amount of knowledge bearing the 
portion of the life-history of the germs CEdogonium of which 
I desire to treat, is very incomplete; there being gaps which 
I think it will be found that what I have seen and have 
to describe, just fit into and fill. The perfect plant itself 
consists of an extremely fine, green-colored filament, 
cylindrical in form, and having its frond divided at regular 
intervals by partition walls so that the individual plant may 
be represented by aseries of tubular cells or boxes, like tall 
pill-boxes, united end to end. The enclosing wall of these 
cells is itself colorless, and it would be difficult to see it, did 
it not possess a different refractive power upon light to the 
water in which it floats. It probably consists essentially of 
the same substance, chemically considered, as the enclosing 
cell-wall of the Desmidiz, and commonly known as cellulose, 
(a term, by-the-way, used in an extremely loos eand indefinite 
manner,) and is possessed of considerable tenacity as will be 
seen to be the case farther on, and is evident by the fact that 
we can handle the filament quite roughly without tearing 
the cells asunder; thus it is common to find this plant 
growing in running water where it withstands the flow of the 
stream. The mode of reproduction known to exist is, as far 
as I can learn, by the shrinking inwards of the inner cell- 
membrane, commonly known as the “ Primordial Utricle” of 
Mohl, and enclosing the cell-contents away from the tough cell- 
ulose coat, while, at the same time, the cell-contents 
themselves assume a more or less coarsely-granular condition, 
apparently from the enlargement of the individual particles 
of which it is made up. It is recorded that thereafter, at a 
certain period in this change, the outer cell-wall splits across 
at a point near to one end of the cell, and, while the lid so 
formed remains attached to one side the other and largest 
portion, the cell-contents escape from the cavity into the 
surrounding water, and gradually assume the spherical form. 
Thereafter there is developed upon one side of the sphere 4 
ring of cilize which become more and more active until, at. 
last, they move about with such energy that the little green 
globe assumes an extremely active motile condition, 
