OF THE FILAMENTOUS ALGJE. 
73 
treated like the rest of the filamentous Algas, because their 
peculiar cell contents fall together and are lost during the 
process of drying, nor can they be restored by moistening 
them. These elegant Algae, therefore, must be preserved by 
Hantzsch’s method. If, however, the student wishes to 
have some specimens in a dried condition, they must be 
treated in the way recommended for the most delicate of 
this class of Algas. There is a circumstance, however, to 
which I would call attention, because it is often looked upon 
as the commencement of a failure. It is, that these plants, 
during the process of drying, invariably lose the rich green 
which distinguishes them in life, and become of a brown or 
black colour, nor does the green ever return. It is a 
curious fact, moreover, that the portion of paper on which 
they have lain assumes a yellow tint on being soaked in 
water. 
With regard to searching for the filamentous Algse, a 
few suggestions remain to be offered. 
The different Vaucherise, Zygnemacese, and (Edogoniaceie 
can be determined only when in fruit ; it is useless to gather 
them at other times. The ripening of the spores is usually 
accompanied with the development of an oily matter, 
having a brown or reddish tint, which frequently gives a 
very pretty appearance to the plants. The red colouring 
so often seen in Sphoeroplea arises from this cause, the ripe 
spores filling the cells in immense quantities. 
The Zygnemacese at some periods of the year are found 
in what is termed a state of ‘conjugation’ — that is to 
say, two filaments lying parallel to each other throw out 
processes by which they become united together. The cell 
contents of one filament are then discharged into the other 
filament, and eventually become spores. Examples of this 
singular mode of propagation are given in Plates xm. (figs. 
66 to 69), xv. (figs. 83 to 85). To find filaments of this 
description search must be made beneath the floating 
masses. They may be distinguished as well by their light 
yellow colour as by the fact of their having a slighter cohesion 
