Mr. HassalPs Notices of British Freshwater Conferva. 391 



I am inclined to regard this as a distinct species ; however, 

 it is perhaps safer to consider it for the present, until it has 

 again been met with in other localities, as a variety. 



I received a fine specimen of it in fructification from that 

 excellent observer Mr. Ralfs, by whom it was found near 

 Penzance. 



Vesiculifera cardiaca. Filaments about equal in diameter to 

 those of the preceding species ; cells five or six times as 

 long as broad ; spores circular, contained in much inflated 

 cells, which may be compared to a heart in form. 

 I have only met with this very distinct species once, in a 



pond near Nofting Hill. There is no other Conferva known 



to me wherewith it could be confounded. 



Vesiculifera ovalis. Filaments more slender than in the pre- 

 ceding species ; cells five or six times as long as broad ; 

 spores oval, contained in cells of a regularly oval form, and 

 not filling the entire cavity of the cells. 

 The above species approaches more nearly than any of the 

 others described in this paper to the figure of Conferva tu- 

 midula in ' English Botany f. the cells are, however, twice as 

 long as they are said to be in that species. From Vesiculifera 

 prolongata it is distinguished by the greater fineness of its 

 filaments, and the more regularly oval form of the spore-bear- 

 ing cells. 



Vicinity of Cheshunt ; very rare. 



Vesiculifera virescens. Filaments equalling in diameter those 

 of Vesiculifera dissiliens ; cells once and a half or twice as 

 long as broad, fasciated ; spores spheroidal, contained in 

 much inflated cells of the same form. 



This at the period of reproduction is a peculiarly elegant 

 species, the elegance of its appearance arising from the grace 

 of form and regularity of disposition of the spore-bearing in- 

 flated cells. 



I have found it in two localities in the vicinity of Notting 

 Hill, near London, 



Vesiculifera dissiliens, Lyngb. et Ag.? Cells scarcely so long 



as broad ; spores circular, contained in inflated cells of the 



same form, which are usually solitary. 



The above is a very beautiful species under the microscope ; 



it is to be distinguished from all others by the shortness of its 



cells. I have preserved several fine specimens of it in seed. 



In the herbarium of Dr. Greville I find a specimen of this 



species, not indeed in a state of reproduction, put up by M. 



Chauvin, and marked with doubt as Conferva dissiliens, Lyngb. 



