ARTHRONEMA. 239 



Harv. in Hook. Br. Flor. p. 366.; Harv. in Manual, p. 155. 



Hah. Borders of lakes at Lismore Island : Captain Car- 

 viichael. 



" It occurs in continuous fleeces parallel to tlie water's 

 edge, of a deep chestnut colour when lying flat, dark olive 

 when floating. The fleeces are made up of small, contiguous 

 fasciculi of interlaced filaments. The filaments are from 

 half an inch to an inch in length, simple or spuriously (?) 

 branched, and prolonged by successive adhesions of portions, 

 seemingly of broken filaments, which at length coalesce and 

 form a knot at the points of adhesion. The transverse striae 

 are close and conspicuous." — Carm. 



Each filament, at regular distances, is obliquely divided : 

 these divisions are not formed by ^^ successive adhesion of 

 portions," but by the partial separation into portions of a 

 single filament, the investing membrane or sheath remaining 

 entire. 



Section ii. Calothricem, 



" I have seen upon a Calothrix, gathered in the ponds of 

 water proceeding from the overflowing of the Seine, se- 

 condary oblong branches formed, which at first sight pre- 

 sented no difierence of organization with that of the principal 

 tube. These branches presented transverse approximate in- 

 ternal divisions, and were filled with endochrome of a very 

 pale green tint. Shortly after their appearance, I have seen 

 the contents of these branches pierce the external envelope, 

 which it left empty and transparent, and issue under the 

 form of a tubular body, oblong, partitioned, obtuse at both 

 extremities Hke the principal filament. Unfortunately I 

 have not been able to follow their developement, because the 

 filaments themselves have become destroyed, or covered with 

 crystals resembling those of Chcetophora.''^ — P. 333. 



Mr. Dillwyn, in his " Introduction to the British Con- 

 fervas," makes some remarks of the same nature in refer- 

 ence to C. distorta. 



