OF THE FILAMENTOUS ALG.E. 73 



treated like the rest of the filamentous Algae, 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 Algse, 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 Algae, a 

 few suggestions remain to be offered. 



The different Vaucheriaa, Zygnemaceae, and (Edogoniaceaa 

 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 Zygnemaceae at some periods of the year are found 

 in what is termed a state of i 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 xiii. (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 



