72 



THE AMEKICAN MONTHLY 



[April, 



of Gloeocystis^ however, are brownish 

 or yellowish. 



We have, however, followed Kirch- 

 ner in this classification, placing Gloe- 

 ocapsa in the family Chroococcaceae, 

 in the order Schizosporeae.] 



9. Genus Urococcus Hassall. 



Cells globular or oblong, large, red- 

 dish or blood-red, with a thick gela- 

 tinous, concentrically laminated en- 

 velope, which forms a thick, annu- 

 larly sti^eaked, apparently articulated, 

 gelatinous stem, which may have a 

 branching character, with the red 

 cells embedded in the ends. 



10. Genus Nephrocythim Nageli. 

 Cells kidney-shaped, 2, 4, 8, or 16 



lying separate in ample kidney-shaped 

 or oval, free-swimming bladders (of 

 the mother cell-wall) ; contents green, 

 with a starch-grain and a vacuole. 

 Propagation unknown. 



11. Genus Oocystis Nageli. 

 Cells oblong, single, or 2, 4, 8, in 



the extended, oblong mother-cell ; 

 contents green. 



[This genus differs from Nephro- 

 cytium only in the oval and not reni- 

 form shape of the cells.] 



12. Genus Gloeococcus A. Braun. 

 Cells oval, green, with colorless 



vacuole, enclosed in ample gelatinous 

 envelopes, which are united into a 

 common thallus. 



Propagation by zoogonidia, with 

 two cilia, produced in the last genera- 

 tion of cells. 



c. Gelatinos^. 



13. Genus Hydrurus Agardh. 

 Cells spherical or elliptic, with 



thick, gelatinous, confluent envelopes, 

 forming a large tubular or worm-like, 

 often branched, attached, gelatinous 

 thallus, sometimes 3 dm. long; con- 

 tents green or brown, cells often color- 

 less at the end. The zoogonidia form 

 single in each mother-cell. 



14. Genus Chromophyton Woro- 

 nin. 



Thallus globose, pulveraceous, 

 eight-celled, floating at surface of 

 water. 



[The genera Hydrurus and Chro- 



mophyton are described by J. Rosta- 

 finskiego* under a new family, Syn- 

 geneticEe, sub-family Chromophyto- 

 ne£e, which includes only these two 

 genera. They closely resemble each 

 other, the principal diflerence being 

 in size and form of the thallus. This 

 author regards the plant as belonging 

 to the Phseoideffi, a new division es- 

 tablished by himself, nearly identical 

 with De Bary's Phseophyce^e.] 



15. Genus Pahnodactylon Nageli. 

 Cells spherical, with thick, vesci- 



cular or confluent cell-walls, en- 

 closed in floating, cylindrical vesicles 

 usually radiately arranged. Cell-con- 

 tents green. 



Division at first in one direction, 

 later in all directions. 



16. Q&\\\x?> Horniospora'Qx&yi%%ox\. 



Cells oblong, arranged in longitudi- 

 nal series, in tubular thallus, simple 

 or branched; floating free. Cell-con- 

 tents green, with a starch-grain at one 

 side. Division only in one direction. 



[This genus is a doubtful one, since 

 it is probably a condition of dissolu- 

 tion of certain filamentous algte.] 



17. Genus Palmodictyon Kiitzing. 

 Cells spherical or oval, with thick 



gelatinous envelopes, one or several 

 cells within single envelope of mother- 

 cell. Gelatinous envelopes connected 

 into a subreticulate or filiform anasto- 

 mosing thallus. 



Propagation by motile gonidia. 



18. Genus Apiocysth Nageli. 



Cells globose, scattered or 8 dis- 

 posed in a circle, embedded in a small 

 gelatinous thallus which is attached 

 by a stem-like base. Cell-contents, 

 homogeneous or firmly granulose, with 

 a distinct chlorophyllous vesicle and 

 colorless vacuole. Tegument thick, 

 dissolving to a homogeneous jelly. 

 Division in every direction. 



Propagation by motile gonidia, glo- 

 bose, with two cilia. 



19. Genus Entophysalis Kiitzing. 

 Cells rotund, associated in families 



surrounded by elliptical mother-cell. 

 Thallus globose, cartilaginous, includ- 

 ing the families of cells. 



* Hydrurus i jego Pokrewienstwo. Krajiow, i88s. 



