Mr. HassaU's Notices of British Freshwater Conferva. 393 



Vesiculifera compressa. Filaments slender; cells twice or thrice 

 as long as broad ; spores contained in inflated cells of a com- 

 pressed ellipsoidal form. 

 The filaments are a shade finer than those of the following 



species, which I have named Vesiculifera sphcerica ; and the 



form of the inflations is also different, being in V. compressa 



not unlike the knobs upon dumb-bells. 

 In Mr. York's brick-field near Cheshunt. 



Vesiculifera sphcerica. Filaments slender ; cells about once 

 and a half or twice as long as broad ; spores spherical, con- 

 tained in enlarged cells of the same form. 

 Vicinity of Cheshunt. 



Vesiculifera fugacissima. Filaments of less diameter than 

 those of Vesiculifera sphcerica, mucous, and of a light green 

 colour ; cells usually as long as broad, but sometimes much 

 longer than broad, at others their breadth exceeds their 

 length. 



Although I have not seen this species in a state of repro- 

 duction, I have but little hesitation in referring it to the genus 

 Vesiculifera, the joints being strongly marked, and when dried 

 somewhat contracted, as is usual with the species of that 'ge- 

 nus. The filaments, notwithstanding their mucosity, do not 

 exhibit any gloss when in a dried condition, in this also re- 

 sembling other Vesiculiferce, 



Cheshunt Common and High Beach. 



Vesiculifera elegans. Filaments slender, but of greater dia- 

 meter than those of Vesiculifera tenuis ; cells about six 

 times as long as broad ; spores oval, contained in greatly 

 enlarged cells of the same form. 



There is not a more distinct or prettier species in the ge- 

 nus, differing from Vesiculifera tenuis in the greater diameter 

 of the filaments. 



I have twice met with it, once near Cheshunt Common and 

 again in ponds on Hertford Heath. 



Vesiculifera tenuis. Filaments very slender ; cells many times 

 as long as broad ; spores oval, contained in cells of a much 

 elongated but regularly oval form. 

 A distinct, graceful, and very rare species. 

 Vicinity of Cheshunt. 



Vesiculifera Mulleri. Filaments very slender ; cells fully four 

 times as long as broad ; spores spherical, contained in in- 

 flated cells of a regularly globular form. 

 This species comes very close to the following. 



