126 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



CL,, figs, ii and 12; P. B.-A., No. 1367. Filaments 22-40 /x 

 diam., cells 3-8 diam. long; conjugation geniculate ; spores 

 short cylindrical, with the ends towards the filaments, about 40 /u, 

 long by 45-60 ti diam.; projecting slightly into the filaments; 

 membrane yellow-brown, smooth. N. H., Mass. Eiirope. 



Wolle's notes on localities for this species are somewhat con- 

 tradictory ; after "Frequent in pond near Worcester, Mass." 

 he adds "The only specimens recognized as possibly of this 

 genus were collected, July, 1880, in Green Pond, New Jersey." 



14. M. TENUIS (Cleve) Wittrock, 1872, p. 39; Plagiosper- 

 mum tenue Cleve, 1868, p. 35, PI. X, figs. 6 and 7. Filaments 

 10-13 /xdiam., cells 8-16 diam. long; one of the conjugating 

 cells dividing into three, the lateral cells remaining sterile while 

 the spore is formed in the central cell, the other conjugating 

 cell being then separated from it by a wall, so that the fertile 

 cell is bounded by three cells, two in the same and one in the 

 other filament. Pa., Florida, N. J. Europe. 



Wolle describes his plant as var. minor, cells 17-18 \i diam., 

 and refers to Cleve's description as giving measurements 25-30 

 /u, diam.; evidently an error. As Wolle's plant is larger than 

 Cleve's there is no need for preserving the varietal name. 



15. M. QUADRANGULATA Hassall, i843b, p. 434 ; M. quadrata 

 Wittr. and Nordst., Alg., Exsicc., No. 61 ; Staurospermum 

 quadratum De Bary, 1858, p. 81, PI. VIII, fig. n ; Wolle, 1887, 

 p. 234, PI. CL, figs. 6-8. Filaments 8-12 p. diam., cells 6-12 

 diam. long, fertile geniculate ; spores quadrangular with trun- 

 cate or incurved angles in front view, i.e. when placed so that 

 the two filaments are in a plane at right angles to the line of 

 vision ; elliptic in form in side view ; occupying the width of 

 both filaments; membrane uncolored, pitted. Mass., N. J. 

 South Carolina. Europe. 



16. M. VIRIDIS (Kiitz.) Wittrock, 1872, p. 39 ; Wittr. and 

 Nordst., Alg. Bxsicc., No. 1591 ; Staurospermum viride De 

 Bary, 1858. p. 81, PI. II, figs. 17 and 18 ; Wolle, 1887, p. 234, 

 PI. CL,, figs. 9 and 10. Filaments 6-8 /x diam., cells 4-10 diam. 

 long ; spores quadrangular, with concave sides ; in side view 

 oblong ; occupying the width of both filaments, outer mem- 

 brane colorless, smooth, depressed at the corners. Fig. 10. 

 N. J., Fla. Europe. 



17. M. ELEGANTULA Wittrock, 1872, p. 40, PI. Ill, figs. 

 5-8; G. S. West, 1905, p. 284. Filaments 4-5 //. diam., cells 

 15-30 diam. long; chromatophore occupying the central two 

 thirds of the cell, with 5-8 pyrenoids ; conjugating cells genicu- 



