248 NEMATOGEN^E. 



Oscillaria zubiginosa. Carmichael Alg. App. ined. 



Stratum gelatinous, dark purple; trichonies very thin, straight, 

 indistinctly articulated, laid on a thin, compact, greenish sub- 

 stratum. 



SIZE. Threads -004-'0045 mm. diain. 



Oscillaria violacea, Rabh. Alg. Eur. ii., 113. Eng. Fl. v. 

 377. 



OsciUatoria violacea, Hass. Alg. 254, t. 72, f. 10. Harv. 

 Man. 166. Johnst. Fl. Berw. ii., 264. 



Conferva mucosa confragosa rivulis innascens, Dillen (?) 



Rapid streams, and on stones at the bottom of rivers. 



When dry the filaments of this species assume a blackish green cast, 

 with an evident gloss. Strige when dried almost invisible, at a distance 

 of about two diameters from each other. Hassall. 



As another species is called Osdllaria violacea (Wallr), which has 

 priority, the name proposed by Carmichael must be adopted. 



Plate XCrill. fig. 0. Portions of trichomes X 400, from the original 

 specimens. 



Oscillaria subfusca. Vauch. Conf.I$3,t.l5,f.5. 



Forming a very thin, greenish brown, then blackish stratum, 

 shortly radiating. Trichomes equal, straight, curved at the 

 apex (curvature of 4 to 5 joints), joints about equal in length to 

 their breadth (after division shorter), dissepiments very dis- 

 tinctly granulate, extreme apical point fimbriate, or bearded. 

 Cell-contents pale greenish steel-blue, granular. 



SIZE. Threads '0045-'006 mm. diam. 



Rabh. Alg. Eur. i., 100. Kirch. Alg. Schl. p. 246. Mack. 

 Hib. p. 240. Eng. Fl. v., 377. Harv. Man. 166. 



OsciUatoria subfusca, Hass. Alg. 253, t. 72, f. 9. 



Attached to wood, rocks, stones, &c., in streams. 



"Stratum extensive, soft, slimy, void of tenacity, wrinkled, of a 

 dusky grey colour, when dry greyish-brown, streaked with green to- 

 wards the edges ; filaments very slender, striae invisible." Harvey. 



Plate XCVL fg. 7. Portions of trichomes X 400. 



Oscillaria aerugescens. Drumm. Ann. Nat. Hist. (1838) i,p. I. 



Stratum of a fine deep green, highly gelatinous, when dried 

 aeruginous blue, and glossy ; trichomes very slender, opaque 

 green, conglomerated in large masses, rarely floating, or broken 

 into fragments and suspended like cloudy flocculi in the water, 

 joints about half their diameter long. 



SIZE. Trichomes '005 mm. diam. 



OsciUatoria aerugescens, Hass. Alg. 249, t. 72, f. 2. Harv. 

 Man. 163. 



