836 AUSTRALIAN FRESHWATER PLANKTON, 



Coenob. (2 cell.) 8-9 x 6-8; (4 cell.) 12-18 x 8-14/x. 



Casino (189) and Lismore (187), Richmond River. 



The outer cells are almost rectangular, sind somewhat securi- 

 form; the central cells are sometimes the same shape, sometimes 

 cylindrical with rounded ends. 



Genus Ankistkodesmus Corda. 

 8yn., Rhaphidiuin Kiltz., Schi'dderia Lemm. 



Ank. falcatus var. mikabims W. ife G. S. West. (PI. Ivii., f.l8). 



Cell long. 36-90, lat. 1-3/i. 



Botany (37, 155); Clyde, Duck Creek (26, 44); Canley Vale 

 ( 1 29) ; Guildford (172); Sydney Water (63) ; Enoggera ; Perth 

 Water. 



8yn., Rhaph. polymorphum var. mirahUe W. k. G. S. West, 

 Frw. Alg. S. of Eng., p.501, P1.7, f.9-13. The contents are 

 generally homogeneous, and of a pale blue tint. 



Var. CONTORTUS (Thuret) mihi. (PL Ivii., f. 19). 



Cell. long. 16-60, lat. 2-3yu. 



Clyde, Duck Creek (26); Canley Vale (129); Botanic Gardens 

 (156); Lismore (258). 



In Brebisson, Liste, p. 158, Pl.l, f.31. I have found this form 

 {n quantity on several occasions. There is a tendency for the 

 apices to be setaceous, but not to the extent of var. setigerus 

 (Schr. setige7-a). 



Ankistkodesmus dulcis, n.sp. (PI. Ivii., f.20). 



Cellulfe solitarite, valde jequaliter arcuatfe, gracillimse, apicibus 

 acutissimis baud autem setiformibus; chloroplastidibus homoge- 

 neis, ab apicibus retractis, medio interdum iiiterruptis; elneoplas- 

 tidibus singulis nonnunquam in extremis, interdum etiam in 

 locello mediano, instructis; pyrenoidibus nuUis. 



Cell. long, (chorda) 30-70, crass. 2-4, alt. 20-40/x. 



Botany(155); Parramatta Park (136); Sydney Water (6 3, 100); 

 Lismore (258). 



