138 



OOCYSTIS AND EREMOSPHiERA, 



chloroplast, not occupying the centre of the semicell. Moreover, 

 the chloroplasts in such cells radiate from this central body to 

 the ends and to the centre. Again, this form of cell always 

 develops a pair of spherical autospores; we may take it, therefore, 

 I think, that such are temporarily binucleated, prior to forma- 

 tion of autospores. We have here also a case of an Ooci/.-tfifi 

 giving rise to the smaller sizes of Eremosphcera; cf. PI. viii., f.20, 

 and Chodat, Bot. Zeit. 1895., T. v., f.8. 



Species unknown to me. 



OoCYSTIS GEMINATA Nag. 



"Familiis e cellulis geminis formatis, cellulis ovoideis, nonnun- 

 quam singulis intra cellulse matricalis membranam vesiculo ampli- 

 atam." De Toni, I.e. 



In Rabenhorst, Fl. Eur. Algarum, iii., p.53 (1868); De Toni, 

 Sylloge Alg., i., p. 664. Syn., Oocystis minor {micrococca) Itzig. 

 0. geminata, in my opinion, is a nomevt delendum. Without 

 figure or dimensions, the expression "cellulis ovoideis^' applies 

 equally well to any number of forms. Every species, also, is 

 capable of developing two autospores to the family. 



Oocystis gigas Archer. 



"Familiis (cellulis initialibus) late 

 ellipticis, subinde quasi globosis, amplis, 

 60-70 X 50-60 /x, plerumque cellulas 2 

 includentibus." De Toni, I.e. 



"O. magna; cellulis solitariis vel in 

 familiis e 2 cellulis formatis consociatis; 

 cellulis late ellipticis, 1 j-plo longioribus 

 quam latioribus, apicibus latissime ro- 

 tundatis et non-incrassatis; contentum 

 chlorophyllosum cellularum granulosum 

 Isete viride." W. West, I.e. 



Cf. Archer, in Quart. Journ. Micr. 

 Sci., 1877, p. 105 (no fig.), De Toni, 

 Sylloge i., 1889, p.665. W. West, New Brit. Frw. Alg., 1894, p. 14; 

 the last-named gives long. cell.40-50-5/x, lat. cell.32-5-40/x; diam. 

 fam. 1 cell. 67 x 52/i. 



Text-fig. 24. 



O. gigas i. minor W. West, 



(x520); after W. West. 



