526 NEW AND RARE FRESHWATER ALG^, 



Merrylands (8ydney) ; Casino (189): Lismore (237. 246, 307, 

 344). 



Yar. ROSTRATUM, n.var. (PI. Ivi., f.l6, 17). 



Cellulse plerumque 4-8 in fascina conjunctse, t'ronte globosoe, 

 pone in rostrum acutum levissime curvatum productae. Cum 

 forma typica atque ejusdem dimensionis. 



Coenobia generally small, with a few cells in a bunch or rosette; 

 cells globose in front, and behind drawn out into a sharp-pointed 

 slightly curved beak; cytoplasm and chloroplast filling the whole 

 cell, only the tip hyaline. Generally no pyrenoid or stigma. 



Genus Volvulina Playf . 

 VoLvuLiNA Steinii Playf. (PI. Ivi., f.l8). 



Coenob. diam. 70, cell. diam. 15, alt. 12/a. Lismore (350). 



In a coenobium of the type with very transparent pale green 

 cells, a minute central nucleus could be observed. The flagella 

 originated close together, and, at their base, two contractile 

 vacuoles, as in 8tein, I.e. In some cells, a large orange-coloured 

 stigma on the margin in front. The inv^esting membrane of the 

 coenobium, as usual, very delicate, and the cells, which were 

 nearly spherical, were pressed close against it. 



Genus V o l v o x Linn. 

 VoLvox AUREUS var. HEMisPHiERicus, u.var. (PL Ivi., f.l9, 20). 



Coenobium rauco investiente tenui; cellulis vertice visis circu- 

 latis, diametro inter se distantibus; a latere plus minusve hemi- 

 sphsericis, basi plana. Cytoplasma granulis magnis amylaceis 

 singulis instructum, stigmate ad marginem; vacuolis contractili- 

 bus 3 circa marginem; pyrenoidi nulla. 



Cell. diam. ^-^|x. Lismore (311, 328). 



The investing mucus of the coenobium very thin, cells quite 

 close to the edge. From above, the latter are circular, about 

 one diameter apart, with a large amylaceous granule towards the 

 centre, stigma at the margin, and three contractile vacuoles at 

 intervals round the circumference. In side-view, the cells are 

 more or less hemispherical, with a flat face closely adpressed to 



