102 OSCILLATORIACE^. 



2. Ly^gsy A. ferruginea, Ag. ; filaments slender, flaccid, curved, forming a thin stratum 

 of a verdigris green colour, which gradually changes to a pale chestnut (but resumes 

 the green in drying), Ag. Syst. p. 73. Harv. Phyc. Brit. tab. 311. L. aeruginosa, 

 Kiitz. Sp. Alg. f. 282. (Tab. XLVII. B.) 



Hab. On muddy shores, in tide pools and floating in ditches of salt or brackish water 

 near the sea. Haarlem River, N.Y. close to the High Bridge, W. H. H. Salt ditches 

 at Hoboken and near Green Port, Professor Bailey, (v. v.) 



Stratum thin, expanded, covering the mud to an indefinite extent, or floating on the 

 surface of stagnant salt water, generally of an intense verdigris or blueish green colour, 

 now and then foxy or rust colour, scarcely at all gelatinous. Filaments about "001 of 

 an inch in diameter, flaccid, slightly flexuous, rather tough, with very thin, membranous 

 cell-walls, filled Avith dense closely and strongly annulated, bluish-green endochrome, 

 occasionally with empty spaces. The striae are very evident. In the dry state the blue- 

 green colour is mostly preserved ; and the surface is not glossy. 



Plate XLVII. B. Fig. 1. Portion of the stratum of Lyngbya ferruginea. Fig. 2. 

 Portion of a filament, magnified. Fig. 3. Section of the same, more highly magnified. 



3. Lyngbya /MZ?;a, Harv. ; filaments slender, elongate, flexuous, fulvous, issuing in 

 erect, crisped, plumose fascicles from a dark coloured stratum ; cell-wall thick, forming 

 a broad limbus to the endochrome. (Tab. XLVII. F.) 



Hab. On the granite masses composing the breakwater at Stonington, Conn. Professor 

 Bailey, (v. s. in Herb. T.C.D.) 



Stratum attached to the rock, dull olivaceous, throwing up long fascicles of filaments, 

 an inch or more in length, and standing upright in the water. Filaments about the 

 size of those of L. ferruginea, but with very thick walls, which form a glassy sheath to 

 the enclosed fulvous or ochre coloured endochrome ; the hyaline border being nearly half 

 as wide as the coloured portion. The annuli are strongly marked and very closely set. 



This somewhat resembles L. luteofusca, Ag., but the walls of the tube are much 

 thicker, as thick in proportion to the enclosed matter as are those of L. majuscula to 

 the matter in its tube. 



Plate. XLVII. F. Fig. 1. Lyngbya fulva, the natural size. Fig. 3. Portion of a 

 filament, magnified. Fig. 2. Section of a filament, more highly magnified. 



4. Lyngbya nigrescens, Harv. ; filaments very slender, flaccid, densely interwoven 

 into a fleecy, blackish-green stratum. (Tab. XLVII. D.) 



Hab. Sea shores or mud, &c. Canarsic Bay, Long Island, Mr. Hooper. Peconic 

 Bay. W. H. H. Also on leaves of Zostera, Peconic Bay, Mr. Hooper. 



