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



G. MUCOSUS A. Braun, 1851, p. 170; P. B.-A., No. 1516; 

 Sphaerocystis Schyoctcri Chodat, 1897, p. 292, PI. IX. Cells 

 6-10 p. diam., colonies 50-1200 ^, perfectly spherical and trans- 

 parent. Common in plankton of quiet fresh water. Fig. 122. 

 Me., Mass. Europe. 



31. GLOEOTAENIUM Hansgirg, 1890, p. 10. 

 Cells globose, subellipsoid, or flattened, united in flattened, 

 rounded families of 2 or 4 cells, with wide and distinctly lamel- 

 late gelatinous walls ; chromatophore a somewhat curved disk, 

 with no pyrenoid ; each family encircled by one or more dark- 

 colored, opaque rings. 



L/ittle is known in regard to the reproduction in this genus, 

 but it is probably, similar to that in Gheocystis ; the only notice- 

 able difference between the two genera is found in the peculiar 

 dark bands, whose nature is imperfectly known. Only one 

 species. 



G. L,OITLESBERGERIANUM Hansgirg, 1890, p. 10 ; G. S. 

 \Vest, 1905, p. 288, PI. CCCCLX1V, figs. 22 and 23. Cells 

 15-24X18-21 /A, united in 2 or 4-celled families; in 2-celled 

 families, including teguments, 42-70X28-40 yu., 24-30 /u, thick ; in 

 4-celled families 60-80X40-60 /x, 30-40 /u thick ; 2-celled family 

 encircled by one opaque band, 10-30 /j. wide ; 4-celled family by 

 two such bands, intersecting on the flat side, and appearing 

 cruciform seen from that side. In still water among other 

 algae. Fig. 109. Trinidad. Europe. 



32. PALMODICTYON Kiitzing, 1845, p. 155. 



Cells similar to those of Gloeocystis ; families of 1-3 genera- 

 tions included in a wide, gelatinous wall ; combined into a gelat- 

 inous, subcylindrical thallus, more or less branching and anas- 

 tomosing ; reproduction by akinetes. 



Differs from Gloeocystis by the combination of the families into 

 a gelatinous thallus of definite shape. 



P. VIRIDE Kiitzing, 1845, p. 155; West, 1904, p. 247, fig. 

 115. Cells 5-9 fj. diam., families up to 50/11 diam.; thallus i- 

 several families \vide, up to 2 mm. long, branching and anasto- 

 mosing freely, the outer layer often more or less reddish. Fig. 

 107. Mass. Europe. 



Family 7. HERPOSTEIRACEAE. 



Vegetative characters and asexual reproduction as in the 

 Chaetophoraceae ; sexual reproduction by autheridia and 

 oogonia transformed from vegetative cells ; oospore spherical, 



