834 AUSTi:\LIAN PUKSHWATER PLANKTON, 



CcELASTHUM OBTUSUM (Eichler) mihi. (PI. Ivii., f.9). 



Celluhe conicrti e basi ipsa protractts; apicibus rotundatis nee 

 truncatis; foramiiiibus amplis. 



Cceiiob. (8 cell.) diani. 24/u. Collector. 



Syii., C. ciibicuiu var. obtustim Eichler, Flory wodor ok. 

 Miedzyr., 1894, i)A'l'2, T. ii., f. 1, where he gives "diam. coenob. 

 l7-2()/x." The cells are conical, drawn out right from the base, 

 with rounded apices. Compare C. ^AsY??t(Zo-fM6 ic?<n?. Schrod., Ploner 

 Berichte, v., 1897, T. iii., especially fig. la. His figures show 

 conclusively that C. probuscidenm Bohlin, C. cubiciim Nag., and 

 this form of Eichler's are, biologically, one species. The last 

 differs too nuich from ('. riibicinn, however, to be placed under 

 that species, and it has priority over C. proboiicideui7i Bohlin, 

 1897. 



Genus S E L E N A s T R u M Reinsch. 



Selenastrum gracile Rein. 



Cell. long. 18-25, alt. c. 18, crass. 3-8/x. 



Botanic Gardens (125) ; Clyde, Duck Creek (26) ; Sydney 

 Water (63); Lismore (182, 260). 



Reinsch, Algenfi. v. Frank., p.65, T. iv., f.3a, b. This species 

 is often found in the forui of two cells back to back. There are 

 generally only a few cells in the ca-nobium. A family of 8 

 coenobia, of 8 cells each, was noted. Solitaiy cells are not 

 uncommon. 



Var. MiNUTiJM, n.var. (PI. Ivii., f.lO). 

 Cellulse dimensionibus dimidio minores quam in f. typica. 

 Cell. long. 9-18, alt. 7-8, crass. l|-2/x. 

 Botanic Gardens (125); Lismore (298). 



Genus S c e N e d e s M u s Meyen. 



Sc. QUADRICAUDA var. INCURVUS, n.var. (PI. Ivii., f.ll). 

 Forma spinis apicalibus incurvis. Ccenob. (4 cell.) s.sp. 30 x 22/x., 

 Centennial Park. 



Cf. Ralfs, Brit. Desm., T.31, f.l2a, b. The terminal spines 

 are generally divergent, but in this form they are incurved. 



