346 FiiESH-wATER ALGiE. \Choros][)ermece. 



analogue of the other, might, a priori, have been conjectured. 

 After the species has been confined for some time, if it be 

 examined with a glass, very many of the filaments will be 

 found to be increased with numerous smaller filaments. 

 These are the young of the plant derived from the growth of 

 zoospores which have attached themselves to the parent 

 filaments. It was the occurrence of a specimen thus in- 

 fested, that induced Yaucher to place this species in his 

 genus Proli/era," It is often covered with a parasite, 

 Diatoyria vulgare, giving it a rich brown instead of its 

 natural rich green colour. 



VAUCHERIA, De CandoUe. 



Gen. Char. Fronds aggregated, tubular, continuous, capillary, 

 coloured by an internal green pulverulent mass. Fructification, 

 dark-green homogeneous vesicles {coniocystce, Ag.), attached to 

 the frond. — The name is in honour of M. Yaucher, a distinguislied 

 writer on Fresh-water Conferva. — Greville. 



This is a very natural and well-defined genus of plants. 

 The structure of the frond is like that of Bryopsis and 

 Codium, but there is no appearance of reticulation or cells. 

 It resembles the Conferva in general appearance, and it is 



