540 



NEW AND RARE FRESHWATER ALG.?:, 



Pediastrum tetras var. Crux MiCHiELi (Rein.) Playf. 



Cell. diam. 18//. Botany (109). (PL Ivii., f.36). 



Noted also in the Sydney Water-supply, these Proceedings, 

 1913, p. 518, PI. 56, f.6. In the specimen here figured, the cells 

 were closely appressed, and the slits were observable through 

 w^iich the zoogonidia had escaped. 



Fam. CCELASTRACE.^. 

 Genus Tetrastrum Chodat. 

 Tetrastrum elegans V, DENTATUM Playf. 

 Coenob. c. spin. diam. 32: corp. 8; sp. long. 12; dent. long. 2-3/z. 

 Lismore (258). 



CJ\ Austral. Frw. Phytopl., p. 833, Pi. Ivii., f. 7. Hitherto 

 known only from Parramatta: this form is now confirmed from 

 Lismore. 



Genus Ccela strum Nag. 

 Ccelastrum reticulatum (Dang.) Senn. (Text-fig. 1 1 ). 



Cellulae matric. diam. 14/x; cell, 

 coenob filial. 6/x. 



Parramatta Park ( 1 36). 

 Syn., Hariotina reticulata Dan- 

 geard, Mem. s. 1. algues, ii., 1889. 

 Generally found in plankton-gath- 

 erings as broken coenobia. Tn this 

 case, six cells were noted, partially 

 united by their processes, each 

 with a perfectly formed autocolony 

 Text-fia.ll.* within. 



EXPLANATION OF PLATES LIV.-LVIll. 



Plate liv. 

 Y'\g.\.~(Mdllaloria^ticxa, n.sp.: ( x (iHO). 

 Fig.'i. — O. simplicissimn v. 'irmntldfa, n.var. : ( x 100<3). 

 Fig.3. — O. simplicisftima v. roiislrirhi. n.var.; ( x HHO). 

 Fig. 4. — O. princeps\-A\\>Aw\-\ ])(>rli(jii of an empty filament, shoAving the 



thick sheath and permanent dissepiment.s; ( k 880). 

 Fig. 5. — FhorinidiHin t/rande, n.sp.; ( x500). 



* Coelastrum reticidatam {Daxig.) Senn, three isolated cells of a ctjeno- 

 bium, each containing an autocolonj^; ( x 1000). 



