AECHER ON ZYGOGONIUM. 121 



the parent conjugating cells ; and, as regards the two bodies, not yet 

 coalesced, represented by him as specially coated by a cell- wall, and 

 separated by a septum from the parent-cells, may they not have been 

 (like the condition in my Fig. 3, lower part) simply the contracted 

 total cell-contents, without any special coat, arrested or caught at the 

 point just before mutual fusion? 



But, great as is the resemblance of the plant figured by de Bary, when 

 we reflect on the beauty and accuracy of his observations in general, it is 

 indeed with difficulty that we can bring ourselves to believe in his having 

 misconceived the character of the plant he describes, and calls Zygogonium 

 didymum ; and if there be really, after all, no such misconception, then my 

 plant cannot be Zygogonium ericetorum, nor any variety, nor can it indeed 

 fall under the genus Zygogonium at all, either as Zygogonium (de Bary), 

 or Zygogonium (Kiitz.) ; for, as already mentioned, as will be seen from 

 the characters above detailed, it must find its place truly in Mougeotia 

 (de Bary, non Agardh). If, on the other hand, de Bary have really 

 erred as regards his plant, the genus Zygogonium, as constituted by 

 him, may possibly not stand, or at least it may have to remain contin- 

 gent on its being necessary to retain it for the common plant Zygogonium 

 ericetorum (Kiitz.) ; for it should not certainly be maintained for those 

 species of Zygnema only which form their zygospores within the trans- 

 verse tube. 



In endeavouring to identify this plant with any form already de- 

 scribed, I venture to think that it comes quite close enough to Zygogo- 

 nium Iceve (Kiitz.) to render it probable that they are indeed one and 

 the same thing, though Kiitzing describes only the barren plant. And 

 if this view be correct, adopting the genus Mougeotia (de Bary, non 

 Agardh), this species should be henceforth called Mougeotia Icevis. 



I have to apologize for the present somewhat roundabout description 

 of this plant. It is not easy to convey at once a definite idea of the 

 points dwelt upon, but I trust my meaning may be sufficiently appa- 

 rent to observers who have made themselves acquainted with the pecu- 

 liarities and the characters of these interesting Algae. Those who have 

 become familiarized with these forms will, I think, well know that these 

 distinctions are by no means imaginary, and will accord with me in feel- 

 ing that they each possess an individuality, and that without much dif- 

 ficulty we can know and recognise the same thing, time after time, 

 when it offers itself to observation ; and that feeling seems to be in- 

 creased and strengthened when, as in the present instance, we are able 

 to follow up the characters of a perhaps tolerably familiar form to its 

 fructification, compare it in its various stages with its allies, and, though 

 they are sometimes hard to describe, note its differences and its idiosyn- 

 crasies. 



George Andrews, Esq., Williamstown Castle, and Dr. David Basil 

 Hewitt, 35, York-street, were elected Ordinary Members of the So- 

 ciety. 



The meeting then adjourned. 



