532 



NEW AND RARE FRESHWATER \LG.V.. 



roplasts radiating out from it, six visible in optical section. It is 

 very difficult to see how they show at the surface, probably as 

 delicate discs. I had hardly finished congratulating myself on 

 this find, when a Chlamydomonas wdth similar cell-contents 

 turned up (from a different pool, however) and cast great sus- 

 picion on its validity as an Oocystis; (see Chi. rotula). 



OocYSTis NODULOSA v. CRASSA, n.var. (Text-fig. 8). 



Forma prse longitudine crassior, 

 subglobosa; membrana crassa; apici- 

 bus et interiore incrassatis et exteriore 

 tuberculatis ut in forma typica. 



Cell. long. 35, lat. '2^-•2^\ cell, 

 matric. 84-7 4/a. 



Lismore (308). 



Cf. W. West, New Brit. Frw. Alg. 

 (J.R.M.S. 1894), Pl.ii., f. 31. Our 

 specimens are larger than the type, 

 and proportionately \ broader, which Text-fig. 8. 



makes them, therefore, subglobose, Oocystk nodulosa var. crassa 

 not oval. W. West gives long. 25-26, "-^^^r., mother-cell with two 



^ J T n T >~ J.1 J- • autospores; ( x 500). 



lat. 1d-1//x as the dimensions. ^ 



Oocystis lacustris v. natans (Lemm.) Plaj-f. (PI. Ivii., f.8, 9). 



Coenob. long. 57, lat. 38; cell. long. 23, lat 121/x. 



Lismore (316). 



Cf. Oocysth and Eremiosph.., p. 125, i.\ih. Our specimens are 

 the same diameter as the type, but a trifle longer; the chloroplast 

 also is more reticulate. The shape of the mother- cell is charac- 

 teristic of 0. lacustris, as also the arrangement of the autospores, 

 I.e., PI. vii., f.20. 



Genus Franc ei a Lemm. 

 Franceia oblonga, n.sp. (PI. Ivii., f.lO). 

 Cellulse oblongse nee ovales; membrana crassa; setis tenuissimis 

 ubique vestitis. 



Cell. long. 15, lat. 10; set, long. 15/x. Lismore (332). 



