338 Mr. HassalFs Notices of British Freshwater Conferva. 



therefore, there is a natural transition from the simple articu- 

 lated Confervae to the branched articulated species, as will be 

 hereafter more fully shown. The affinities of this genus have 

 not hitherto been at all understood. M. Decaisne has like- 

 wise observed the passage of the contents of one cell to those 

 of a neighbouring cell in Bidbochate setigera, but does not 

 draw the inference from it which I have done.] 



The facts in favour of this view of the reproduction of the 

 group are the same as those mentioned in reference to the 

 Zygnemata already alluded to, viz. the non-union of the fila- 

 ments, and the disposition of spores and empty cells, the spores 

 in most of the species of the genus being solitary and lodged 

 in the inflated cells. In some species however inflated cells, 

 amounting to five or six in number, sometimes occur in juxta- 

 position, and this would appear at first sight opposed to the 

 view adopted ; and did each inflated cell contain a perfect 

 spore, this one fact would be altogether irreconcileable with it ; 

 but I am of opinion that many do not, which opinion is sup- 

 ported by the circumstance, that in a variety or condition of 

 Zygnema porticale which I have recently met with, the fila- 

 ments of which do not conjugate but still produce seeds, 

 many of the inflated cells do not contain spores, as may be 

 plainly seen, owing to the transparency of the filaments. 



It is at once apparent that the mode of reproduction just 

 indicated does not differ essentially from that first made 

 known by Vaucher with reference to the Conjugates, and espe- 

 cially in respect to those most interesting species which I 

 have described as producing true spores without union of the 

 filaments, nor from that of the Spharopiets. In all these it is 

 virtually the same, and to these groups I believe all the known 

 species of true articulated freshwater Confervae with simple 

 filaments may be referred, excepting only Conferva mucosa 

 and C. punctata. They are all perpetuated by means of true 

 spores, these spores being formed in all cases alike, by the 

 union and intermingling of the contents of two distinct cells 

 placed either in the same or different filaments. 



This opinion, which, being founded on careful and long-con- 

 tinued observation, I trust will stand the test of innovating 

 time, by which the value of all things must finally be proved, 

 is now for the first time promulgated. It w T as, of course, 

 known that the spores of the Conjugates were produced in this 

 way, but it has not, so far as I can learn, been even hinted 

 that the same phaenomenon was applicable to all freshwater 

 Confervae with simple filaments, exclusive of the two species 

 mentioned above. 



The discovery of this identity in the mode of reproduction 



