CONFERVACEtE. 73 



species of a green colour formerly referred to the genus Conferva. The species are 

 extremely difficult to define, and have been unreasonably multiplied ; but are so mucli 

 diversified that it is difficult to avoid giving diiferent names to the many forms met 

 with, if they are to be described at all. Kiitzing admits 210 species, and probably 

 nearly 100 more have been described by other authors. A wholesale reduction will 

 probably be eventually made. I have referred most of the American forms, approxi- 

 mately or absolutely, to European types ; in some cases perhaps incorrectly. But 

 unless better specific characters than those at present in use shall be discovered, it is 

 almost impossible to find words to characterise, as distinct, nearly allied forms. When, 

 therefore, I meet with an American specimen reasonably like a European, I here place 

 them under the same head, or specific name. Several doubtful specimens I have been 

 unable satisfactorily to identify, and hold them over for future examination, should 

 better materials be sent to me. 



Sect. 1. — Species found in the sea. 



* CjESPITOS^. Filaments short, rigid, densely interwoven into cushion-like tufts. 



1. Cladophora repens, J. Ag. ; filaments short, emitting root- like processes, densely 

 interwoven into globose or expanded mats, capillaiy, rather rigid, sparingly and very 

 irregularly branched ; branches erect, subsimple, filiform, naked or having a few secund 

 ramuli ; articulations cylindrical, many (10-20) times as long as their diameter. 

 J. Ag. Alg. Medit. p. 13. Harv. Plnjc. Brit. t. 236. Kiitz. Sp. Alg. /). 416. 



Hab. On rocks, &c. in the sea. Key West, W. H. H. (v. v.) 



Tufts very dense, an inch or two in breadth and about half an inch high, cushion- 

 like, composed of innumerable, interwoven, capillary filaments. The filaments are at 

 first decumbent, and connected by rootlike fibres which form the substratum of the 

 mat ; the branches are erect, simple or branched, with or without secondary ramuli. 

 The articulations vary greatly in length in specimens from difierent localities. 



This species is a native of the Mediterranean, and also of the British Channel Islands. 

 Except in the length of the articulations, which also vary much in the same filament, 

 the European and American specimens nearly coincide. 



2. Cladophora membranacea, Ag. ; filaments short, creeping, densely interwoven into 

 globose or expanded mats, somewhat fastigiate, thick, almost setaceous, flaccid, mem- 

 branaceous, sparingly and irregularly branched ; articulations many times longer than 

 broad. Ag. Syst. p. 120. Kid:. Sp. Alg. p. 415. 



Had. On rocks and the smaller Algae. Key West, W.H.H., Professor Tuomey. 

 (v. V.) 



