BY G. I. PLAYFAIR. 837 



Var. ciNGULUM, n.var. (PI. Ivii., f.21). 



Cellulsi? magis aifuatae, ti'es quadrantes circuli etRcientes, apici- 

 l>us niodice ineurvis. Cell. long, (chorda) 26, ci-ass. 2, alt. 20ju. 



Botany (92). 



A very pretty species, both from its graceful cinvatiu'e and 

 from the disposition of the cell-contents. The cell has the 

 regularl)' arched form of a C/ostfrlnm, very slender and gradu- 

 ally narrowing to the ver\^ acute tips. The latter are not di'awn 

 out into seta?, and are not incurved. The homogeneous chloro- 

 plast is generally confined to the body of the cell, leaving the 

 tips clear; it is also often interrupted in the centre, or there is a 

 locellus at the centre, placed to one side. Very often, an elajo- 

 plast is situated at each end of the chloroplast, sometimes also 

 one in the middle. In var. cingulum, the curvature extends 

 over three parts of a circle, the ends being somewhat incurved. 



Ankistrodesmus Braunii (Nag.), forma. (PI. Ivii., f.22). 



Cell. long. 40, lat. 3//. Lismore (196). 



The figure shows four cells, produced by longitudinal division, 

 and still connected by the membrane of the mother-cell, which 

 has become twisted into a stipes. 



Var. MINUTUS, n.var. (PI. Ivii., f. 23-25). 



Cellulfe parvse, longitudine usque ad formae t3'pic8e dimidium. 



Cell. long. 10-20, lat. 2-3 (rarius 5) /x. 



Lismore (182, 191, 196). 



Cells only half as long as those of the type (or less), and gen- 

 erally a little more lunate, sessile on })ieces of flocculent matter, 

 water-plants, etc. 



Genus A c T I N A s T R u M Lagerh. 

 AcTiNASTRUM Hantzschii Lag. (PI. Ivii., f.26, 27). 



Coenob. (2 cell.) diam. 54, cell. 25 x 4; (4 cell.) diam. 28-50, 

 cell. 16-25 X 2-4; (8 cell.) diam. 40-50, cell. 20-30 x 2-3/x. 



Parramatta(136); Botany(50); Lismore (258); Grafton, Nym- 

 boidia River(269). 



