THE GREEN AI.GAE OF NORTH AMERICA 115 



and Wolle's statement as to Pennsylvania localities was the 

 first record for spores of this species ; in Massachusetts it was 

 found sterile, attached to stones, also floating, with spores like 

 those figured by Wolle. 



25. S. BELUS (Hass.) Cleve, 1868, p. 18, PI. Ill, figs. 2-5; 

 Petit, 1880, p. 31, PI. X, figs. 1-3; Wolle, 1887, p. 217, PI. 

 CXXXVII, figs. 5 and 6; PI. CXXXIX, figs, i and 2 ; P. 

 B.-A., No. 359. Filaments 65-80 //. diam., cells 1^-3 diam. 

 long ; chromatophores 5 or 6, narrow, with large prominent py- 

 renoids ; almost straight, or making half to three-quarters of a 

 turn in a cell ; fertile cells swollen and shortened ; swelling 

 sometimes only on the side opposite to the conjugation ; spores 

 brown at maturity, lenticular, diam. 84-90 p., thickness 55-60 //.. 

 Mass., N. J., Pa. Europe. 



26.. S. DUBIA Kiitzing, 18553, p. 8, PI. XXIV, fig. 4; 

 Wolle, 1887, p. 220, PI. CXXXV, figs, ii and 12. Filaments 

 43-5 P- diam., cells i}4-2}4 diam. long; chromatophores 2, 

 rarely 3, narrow, making 1-3 turns in the cell ; fertile cells 

 slightly swollen ; spores brownish at maturity, ovoid-ellipsoid, 

 about 40 /u. diam., 1-2 diam. long. Mass., Pa. Europe. 



Var. LONGIARTICULATA Kiitzing, 18553, p. 8, PI. XXV, 

 fig. i ; Wolle, 1887, p. 220; P. B.-A., No. 961. Cells 5 diam. 

 long; chromatophores 2 or 3. British Columbia. Europe. 



Subsection MONOZYGA ; only one cell emitting a tube. 



27. S. PUNCTATA Cleve, 1868, p. 23, PI. VI, figs. 1-4; Petit, 

 1880, p. 24, PI. IX, figs. 9-n ; Wolle, 1887, p. 215, PI. CXU, 

 fig 8 - 5'7- Filaments 24-27 /u diam., cells 6-12 diam. long; 

 chromatophore single, rather slender, with few pyrenoids, mak- 

 ing 4-7 turns in the cell ; fertile cells swollen and shortened ; 

 tube issuing from only one of the conjugating cells, broadening 

 until it reaches the surface of the other cell ; spores ellipsoid, 

 yellowish at maturity, 1^-2 diam. long, about 36 /u. diam.; 

 median membrane finely punctate. N. J. Europe, Asia. 



The punctate membrane and the peculiar formation of the 

 tubes amply distinguish this from all our other species. The 

 latter character shows a more distinct sexual differentiation 

 than in other species of the genus. 



Section 2. SALMACIS ; Dissepiments replicate. 



28. S. TENUISSIMA (Hass.) Kiitzing, 1849, p. 437; Petit, 

 1880, p. 6, PL I, figs. 1-3; Wolle, 1887, p. 207, PL CXXXII, 

 figs. 1-3 ; P. B.-A., No. 456. Filaments 9-12 /* diam.; cells 

 4-12 diam. long; chromatophore single, slender, making 3-5^ 



