CONFERVA BIPARTITA. 



C. filamentis limplicibus, tenuibus, longiflimis, denfiffime compaftis, flavo 

 virentibus; articulis diametro fub triplo longioribus dtnium bipartilis. 



In fmall Pools on the Cogs on Town Hi!i Common, near Southampton. Mr. 

 Woods. 



In the Ditches between Pontardylais and the Sea, Carmarthenfhire. 



THE prefent fpecies almofl fills the ditches in the marfhes between Pontardy- 

 lais and the fea, and I cannot find that it has been heretofore defcribed. It 

 floats on the furface of the water in large denfely matted, maffes, of a yellowifh 

 green color, and retains air bubbles in the fame manner as thofe fpecies which 

 were formerly confounded together under the name of C. bullofa. The fila- 

 ments are very long, unbranched, and in thicknefs rather exceed thofe of C. 

 vivularis. The length of the joints is ufually from three to four times their 

 diameter. At a certain age the interior of each joint feparates by a tranfverfe 

 divifion in the middle, into two veficles, which at length contract and become 

 rounded at the corners. In figure B, the filament marked No. I is in its youngeft 

 ftate : in the lower part of No. 2, the tranfverfe feparation of the joints has juft 

 commenced, and it is feen in the different ftages of advancement towards the 

 upper end of the fame filament and in No. 3. Thefe internal veficles when 

 thus contracted are fometimes difpofed, as is reprefented at No. 4, and it fre- 

 quently happens that the division has commenced at one fide of the filament and 

 not on the other. The plant figured at C grew in the fame place and manner 

 with the foregoing, and could only be diftin uiihcd by the microfcope. I found 

 the filaments of both mixed with each other, and the joints of many were fo 

 intermediate as to prove that both belong to the fame fpecies. 

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