THK GREEN ALGAE OF NORTH AMERICA 429 



14. V. PILOBOLOIDES Thuret in Le Jolis, 1863, p. 65, PI. 

 I, figs. 4 and 5; Woronin, 1869, p. 153, PI. II, figs. 18-29; p - 

 B.-A., No. 476. Marine; filaments usually 40-60 p diam., 

 sometimes 80 /u. ; antheridium terminal, separated from the fil- 

 ament by an empty cell, cylindrical, acute, with one or two 

 lateral, conical projections ; oogonium terminal, usually on a 

 short branch near the antheridium, clavate with a spherical 

 summit, up to 200 p. diam. ; oospore lenticular with thin mem- 

 brane, 150X80-100 p.; aplanospores 250X80 p., formed at the 

 ends of the branches, expelled from the sporangium at maturity. 

 Muddy and sandy places, below low water mark. Conn. 



Var. COMTACTA Collins, 1900, p. 13; P. B.-A., No. 477. 

 Tufts very densely matted ; oospores usually spherical, occa- 

 sionally lenticular ; oogonia and antheridia scattered without 

 definite relation to each other. Salt marshes, on mud near high 

 water mark. Mass.. 



The dense, plush-like coatings of this variety are indistin- 

 guishable from V. Thuretii, that grows in similar locations ; but 

 the fructification is quite distinct. 



15. V. SPHAEROSPORA Nordstedt, i878a, p. 177, PI. II, 

 figs. 7 and 8 ; Phyk. Univ., No. 282. Marine ; filaments 25-60 

 p. diam., loosely tufted ; antheridium at the somewhat swollen end 

 of a branch, generally slightly curved, acuminate, bearing just 

 below the summit two conical, subopposite processes ; oogonium 

 below on the same branch, separated by an empty cell, globose 

 or obo void-globose, 105-135 p. diam. ; oospore green, with thin 

 membrane, 85-125 p. diam., not filling the oogonium. Green- 

 land. Northern Europe. 



16. V. INTERMEDIA Nordstedt, 1879, p. 179, PL I, figs. 

 10-16; Wittr. & Nordst., Alg. Exsicc., No. 334. Marine; fila- 

 ments 35-65 p. diam. ; oogonia subsessile or shortly pedicelled, 

 globose or ovoid-globose, 90-130 p. long., 95-115 p- wide, with one 

 short and broad tube ; antheridium single or often two, 20-30 p. 

 diam., usually straight with rounded, truncate apex, and 2-4 

 very short, lateral tubes ; oospore globose, with thin membrane, 

 85-120 p- diam., almost filling the oogonium. Greenland. 



Northern Europe. 



17. V. CORONATA Nordstedt, 1879, p. 177, PI. I, figs. 1-9; 

 Wittr. and Nordst., Alg. Exsicc., No. 1022. Marine ; filaments 

 48-70 p. diam. ; oogonia solitary, subsessile, borne on the branches 

 bearing the antheridia, more rarely on the main filaments, 

 obovoid or obliquely ovoid, 125-145 p. long, 145-180 p. wide, 

 bearing at the top a circle of 3-6 tubes for the entrance of the 

 spermatozoids ; oospore globose or subglobose, 115-135X115- 



