222 MONOCYSTEJ5. 



and length of the cells vary considerably, according to the 

 age of the plant. 



3. Lyngbya copulata Hass. 

 Plate LXXII. Fig. 14. 



Char. Filaments very flexible, of about the same diameter 

 as those of L. muralis, adherent to each other for a con- 

 siderable portion of their length. Cells short. 



L. muralis var. copulata Carm. MS. 



Hab. Appin; Captain Carmichael. 



This is a very curious production, exhibiting some relation 

 in the adherence of the filaments the one to the other to 

 Calothrix mirabilis — than which it is not less wonderful. 

 It is very rare. 



4. Lyngbya virescens Hass. 



Plate LX. Fig. 3. 



Char. Filaments of about the same diameter as those of L. 

 punctalis. Cells usually somewhat beaded, rather longer 

 than broad. Endochrome not quite filling their cavities. 

 Hab. On stones, in a pond, near Wanstead Flats, Essex : 

 A.H.H. Penzance: Mr. Ralfs. 



This S23ecies, except in the simplicity of its jSlaments, bears 

 a very close rjesemblance to the Draparnaldia. Like the 

 species of that genus, it is of a beautiful green colour, fragile, 

 slippery to the touch, and delighting in pure and slowly run- 

 ning waters. The filaments are always attached, in which 

 respect it agrees with L. zonata. 



5. Lyngbya Thompsoni Hass. 



Char. Filaments attached, exceedingly slender. Cells once or 

 twice as long as broad. 

 Meloseira Thompsoni Harv. in Manual, p. 195. 



