430 Mr. Hassall's Notices of British Freshwater Conferva. 



" It differs from all the other Vaucheria by the manner in 

 which it carries its grains. The peduncles which sustain them 

 are very much elongated ; they bear at their extremities two 

 little threads, the one curved, into which is inserted the anther ; 

 the other, shorter and straighter, carries the grain. This 

 Conferva expands its grains at the commencement of spring. 

 I have seen it germinate in such a manner as that I doubt not 

 that these grains are really the seed." — Vaucher. 



This is an abundant British species : I have met with it re- 

 peatedly in the vicinity of Cheshunt and other places during 

 the springs of the past and present years. 



Vaucheria repens. Filaments ten-estrial ; capsules sessile, so- 

 litary and avicular, or in the form of a bird's head ; anthers 

 cur\-ed and placed in close approximation with the capsules. 

 I have as yet been able only to find but one specimen of 

 this species, which is to be distinguished from Vavcheria Dill- 

 wynii, the only species near to which it approaches, by the 

 form of the capsules, which in the latter species are spherical. 

 In a foot-path near Roydon, Essex, February 21st, 1843. 



Genus Zygxema. 



Obs. Having recently had the opportunity of re-examining 

 two of the three species of non-conjugating Zygnemata de- 

 scribed in a pre\aous paper, viz. Zygnema angulatum and Z. 

 intermedium, as well as many other species not yet described, 

 I have been able not merely to confirm the general accuracy 

 of the statement formerly made of the production in certain 

 species of spores without conjugation of the filaments, but 

 also have ascertained two other particulars in reference to 

 these most interesting productions. 



The first of these relates to the fact, that union of the fila- 

 ments does in some rare cases occur even in those species, in 

 which the rule is, that the spores should be formed without 

 conjunction ; and this is nothing more than from analogy 

 might clearly have been expected, nor does it in any way affect 

 the importance or truth of the fact of the formation of spores 

 in separate filaments. 



The second particular is one of much interest, and has re- 

 ference to the circumstance, that in some few instances more 

 than two apparently perfectly formed spores — three, four, or 

 even five — are placed in adjacent cells, and consequently that 

 no empty cells intervene between them, as we should expect to 

 find in all cases, were it an essential, that every true spore should 

 consist of the mingled contents of two cells. But this is only 

 an apparent exception to the law of the formation of spores by 



