BY G. I. PLAYPAIR. 127 



of Cambridgeshire, Juuru. Bot, 1.S09, Pl.oOl, f.U-17. Dimen- 

 sions given are long. cell. 6-12, lat. cell. 4-7.; long. teg. 13-5-29, 

 lat. 10'5-l(S/x. O. jmrva might very well be arranged as a varia- 

 tion of O. lacustris. 



OocYSTis NODULOSA W. West. (Text-fig. 16). 



"O. mediocris; cellulis solitariis vel in familiis e 2 cellulis 

 formatis consociatis, cellulis oblongo-ellipticLs, 1^-plo longioribus 

 quam latioribus, apicibus late-rotundatis et nodulis incrassatis." 

 W. West., I.e. 



Cf. West, New Brit. Frw. Alg., p.l5, PI. ii., f.:U, 189-1. Syn., 

 0. crassa y nodnlosa Chodat, Alg. vertes, p. 190. I have not 

 found the type. 



Yai'. AUSTRALis, n.var. (PI. vii., f.27, 28). 



Forma paullo magis oblonga; membrana ad polos introrsum 

 tantum incrassata. 



Cell. veg. 21 X 12, 2:^ x 13, 25 x 15, 

 26 X Ujj.. 



Botany Bay (91); Auburn (57). 



This is a very rare foi-m; a few spe- 

 cimens were noted in No. 91 among 

 quantities of free cells of O. Ndgelii. 

 Our specimens differ somewhat from Text-fig. 16. 



the type; they area little more oblong, ^""y'''' "«*''«•*« W. We.st, 



, , , . . . . f (X 520); after West. 



and the polar mcrasvsation is entirely 



on the inner side of the membrane. West gives long. 25-26, 



lat. 16-17/x as the dimensions of the type. 



OocYSTis SOLITARIA Wittrock. (PI. vii., f.29). 



Cell. veg. 18 X 11, 18x 12, 20 x 10, 21 x 11, 21 x 12, 22 x 1 1, 

 22 X 13, 23 X 1.5, 24X15/X. 



Guildford (146); Auburn (57); Duck Creek, Clyde (71). 



In Wittrock et Nordstedt, Alg. iu[. dulc. cxsicc, No.241, IS79: 

 Bot. Notiser, 1S79, p. 24; G. S. West, P.i'it. Frw. Algu>, p. 227, 

 f.97A, B. Very rare in this country, though "undoubtedly tli<' 

 commonest species" (G. S. West, /.<•.) in Bi'itain. The Hguic in 



