BY G. I. PLAYFAIU. lOl 



Var. Casinoensis, n.var. (PL iii., f.5). 



Forma semicellulis sciagraphia CI. aceroso consimilis ad polos 

 non recurvatis, infra apices seriebus singulis nodulorum incrass- 

 atorum circ. 10 ornatis. Membrana dilute rufescente, dense 

 scrobiculata, utrinque ad nodulos longitudinaliter striata; inter- 

 dum membrana glabra vel subtilissime striata. 



Long. 560-640, lat. 44-50, ap. 6 /x. 



Casino (14). 



This is almost the exact shape and size of CI. turgidum f. 

 glabra Gutw., Nonn. Alg. Nov., p. 5, T.v., f.lO. The scrobiculse 

 are on the inner side of the membrane, which is striate just for 

 a short distance above and below the incrassations. The striae 

 run alternately through and between the incrassations. 



Other forms of Closterium noted were CI. acutum and var. 

 linea, CI. gracile, CI. corriu. The plankton-forms, CI. gracile var. 

 elongatum W. &l G. S. West, and CI. actitujn var. subpronum 

 (W. & G. S. West), which might have been expected, and are 

 not uncommon round Sydney, were not observed. The current 

 of the river, however, is very sluggish. 



Genus Cosmarium Corda. 



COSMAKIUM ANdULATUM f. MAJOR Grun. 



Long. 70-82, lat. 44-48, ap. 20, isth. 15-16, crass. 30 /x. 



Lismore(12), Casino (14). (PI. iii., f.6 ). 



Syn. Cos. Bengalense Turner, Alg. E. Ind., T.8, f.33, and T.9, 

 f.33. A very rare desmid this, only twice noted before, viz., 

 from Banka I. and Bengal. Cf. Grunow, Insel Banka, T.ii., f.24, 

 (whose figure works out at 63 x 40 /x) and Turner, I.e., p. 56, T.8, 

 f.35, and T.9, f.25. Our specimens are not so retuse in the sides 

 as in Grunow's figure. Membrane smooth but sometimes faintly 

 and closely pustulate, and there were no signs whatever of the 

 inflations indicated by Grunow. When the chloroplasts are in 

 good condition, their surface is divided into minute digitate 

 fibrilhe, as noted by Turner, I.e., and Wallich. They are most 

 noticeable at the isthmus. My opinion of this desmid is that it 

 is 2b forma maxima of Cos. Meneghinii. 



