THE GRKEN ALGAE OF NORTH AMERICA 309 



3. G. GIGAS (Kiitz.) Lagerheitn, 1883, p. 63; Phyk. Univ. 

 No. 638 ; G. amp/a Wolle, 1887, p. 196, PI. CLVI, figs. 2-8. 

 Cells globose or oblong-ellipsoid, 9-12 p. diatn., solitary or 2-8 

 forming a family 45-95 /" diam. ; membrane thick, distinctly 

 lamellate ; contents green, but containing brownish oil globules ; 

 forming gelatinous, roundish, dull green or brownish masses on 

 submerged objects. Me., Mass., W. I. Europe. 



When the brownish oil drops are abundant, it is called var. 

 nifescens, but the distinction is not worth a name. 



4. G. PAROLINIANA (Menegh.) Nageli, 1848, p. 65; Phyk. 

 Univ., Nos. 23, 597 ; Microcystis Paroliniana Meneghini, 1842, 

 p. 78, PI. X, fig. 2. Cells 3-6 p- diam., globose, 2-8 forming a 

 family not over 24 p. diam.; membrane hyaline, lamellate ; con- 

 tents yellowish ; forming a firm incrusting stratum on wet rocks, 

 etc., about 2 mm. thick. Mass., N. H., Canada. Europe. 



Distinguished by the yellowish color, and the small families 

 united into a firm stratum. 



5. G. zostericola (Farlow) nov. comb.; Gloeocapsa zosteri- 

 cola Farlow, 1882, p. 68; Gheocystis chrysophthalina P.B.-A., 

 No. 219. Marine; cells spherical or by mutual pressure 

 flattened-hemispherical, 19-26X9-11 p-, 2-4 united to form a 

 family 40-100 p. diam.; membrane ample, lamellate; contents 

 brownish; forming brownish masses on Zosfeni marina. Wood's 

 Hole, Mass.; has not been observed elsewhere. 



6. G. FENESTRAI.IS (Ku'tz.) A. Braun in Wittr. and Nordst., 

 Alg. Exsicc., No. 444; P. B.-A., No. 566; Gloeocapsa fencs- 

 tralis Kiitzing, 18493, PI. XV, fig. 5. Cells globose or oblong, 

 2-4.5 /" diam., with membrane 7-15 n, solitarj^ or 2-18 forming a 

 family, 15-50 /u, diam.; membrane hyaline, thick, lamellate, 

 chromatophore bright green ; forming a thin, soft, pale or }-el- 

 lowish stratum in greenhouses, etc. Mass., R. I. Europe. 



7. G. SCOPULORUM Hansgirg in Foslie, 1890. p. 155 ; Col- 

 lins, igoSa, p. 155. Cells 4-6 p. diam., united in colonies of 2-8 

 cells, envelop distinctly stratified ; forming greenish-yellow 

 gelatinous masses in company with other minute algae, near 

 high water mark. Me. Europe. 



A doubtful species ; possibly a state of Ulothrix or Urospora. 

 30. GLOIOCOCCUS A. Braun, 1851, p. 170. 



Cells globose, enclosed in greater or less number in an ample 

 globular transparent gelatinous mass ; with bell-shaped chroma- 

 tophore and one pyrenoid. Asexual reproduction by division 

 of a cell into four daughter cells, by the formation of aplano- 

 spores, and by the formation of biciliate zoospores, of two sizes. 



