BY G. I. PLAYFAIR. 117 



Algj\^, J.R.M.S., 1894, with notes on 14 forms of Oocystis (S 

 species, including 3 new). De Toni's .Sylloge mentions only 9 

 species (all published at that time) of which two appertain to 

 another genus. In the present paper, 31 published species* of 

 Oocystis are discussed. Of these, two {0. geminata Nag., and O. 

 brunnea Turn.) have been practically set aside, one(C'. maviut Hi- 

 lda Turn.) is considered xevy doubtful, three {0. sptujera Arch., 

 0. cilia/ a Lag., and 0. Echidna. BohVm) have long ago been 

 relegated to Lagerheimia (including ChodateUa), foui- are reduced 

 to variations, seven ranked as synonyms, leaving us with fourteen 

 fairly valid types. Tn addition to these, six new species are pro- 

 posed. Every described vai'iation or foi-in has been included in 

 my notes, with many others that seem to be new. Together, they 

 amount to twenty-five, nineteen variations, six forms. In nearly 

 every case, the original description and figure have been added. 



With regard to Eremosphcera viridis, I consider it to be a 

 species of Oocystis, but I have not altered the nomenclature. 

 Several new forms are described and figured. 



Genus Oocystis Nageli. 



"Oocystis .... genus Nagelianum ineditum" . . . ., A. Braun, 

 Alg. unicell. (1855),t p.94, footnote. ^yn., Oocystella Lemm., 

 Zeitschr. f. Fischerie u. d. Hilfsw., 190-3. 



Oocystis N^gelii A. Br. (PI. vii., f.1-6). 



"Species nova minime rara, cellulis oblongis viridibus, nunc 

 solitariis, nunc binis, quaternis avit octonis cellula mati'icali mem 

 bi'anacea forma simplici inclusis." A. Bi-aun, I.e. 



Cell, veg., 17x10, 18x8, 18x10, 19x9, 19x10, 20x8, 

 20x9, 20 X 10,20 X 11,21 x 12, 22 x 11, 24 x ll,24x 12,24 x 14, 

 25 X 14/x. 



Guildford (60, 88, 114, 146); Sydney Water (67); Botany Bay 

 (91); Auburn (57); Duck Creek, Clyde (74). 



* Including Cyfindroci/fitis oralis Turn., Hydrocytinm macroi^pornm Turn., 

 Oocystella natans Lemm., and 0. spec. Schm. These .31 are all tliat I 

 know of up to date. 



fBy printer's error, 1845 in G. S. West, Brit. Frw. Algce, p.227. 



