66 DR. G. S. WEST ON THE ALG.E OF 
38. ARTHRODESMUS TRIANGULARIS, Lagerh. in Ofcers. К. Vet.- Akad. Förh. 
xlii. (1885) p. 244, t. 27. fig. 22. 
Forma MINOR. [=А. /neus, forma, Racib. in Rospraw. Wydz. matem."przyr. 
Akad. Umiej. Krakow. ser. 2, xxii. (1892) p. 877, t. 7. fi 
forma Saidæ, Kich. $ Racib. ibid. xxvi. (1893) p. 120. | 
Long. 17-18 ш; lat. s. spin. 115-125 p, c. spin. 35-379 ш; lat. istbm. 4 д. 
Hab. Yan Yean Reservoir, in the plankton and at the weedy margin. 
g. 25 ; А. Incus, 
Genus STAURASTRU M, Meyen. 
39. STAURASTRUM MUCRONATUM, Ralys, in Ann. Nat. Hist, (1845) р. 152, 
1. 10. fig. 6. 
Var. DELICATULUM, G. 8. West, in Victorian Naturalist, xxii. (1905) p. 72 ; 
in Journ, Bot. xliii. (1905) p. 254. 
Var. semicellulis elliptico-fusiformibus, angulis lateralibus submamillatis 
et delieatissime apiculatis. 
Long. 3275-35 и; lat. 34-37 ш; lat. isthm. 6-7 ш. (Pl. 5. fig. 5.) 
Hab. Yan Yean Reservoir, in the plankton (very common, Feb. and Mar. 
1905) dnd at the weedy margins (very rare, May and July, 1905). 
40. STAURASTRUM MUTICUM, Breb. in Menegh. Synops. Desm., Linnwa 
(1840) p. 228 ; in Ralfs, Brit. Desm. (1848) р. 125, t. 21. fig. 4, t. 34. 
fig. 13. 
Var. VICTORIENSE, G. S. West, in Viet. Nat. l. е. з Journ. Bot. l. c. 
Var. cellulis longioribus quam in forma typica ; semicellulis late ellipticis ; 
membrana delicatissime punctata. 
Long. 30 ш; lat. 20:5 w; lat. isthm. 7*5 и. (PI. 5. fig. 8.) 
Hab, Yan Yean Reservoir, in the plankton (most abundant from Mar. to 
May, 1905) and at the weedy margins (common in June, 1905). 
41. STAURASTRUM DIGITATUM, sp. п. (PI. 5. figs. 11-12.) 
S. parvum, circiter 13-plo latius quam longum (cum processibus), leviter 
constrictum, sinu ininuto ; semicellulæ subglobosæ, cum processibus elongatis 
glabris et leviter divergentibus apicem versus utroque, processu unoquoque 
gradatim attenuato sed constrictione minuto ad basin, apicibus processuum 
obtusis; a vertice vise corpore circulari, eum processibus elongatis glabris 
4-5-radiatis ; membrana tenue et glabra. 
Long. s. proc. 19-21 р, е. proc. 30-32 и; lat. s. proc. 12-15 р, c. proc. 
48-52 д; lat. isthm. 8-975 p. 
Hab. Yan Yean Reservoir, at the weedy margins (Mar. and Apr. 1905). 
This species is a close ally of S. lerispinum, Bissett, 5. sublevispinum, 
W. & С. S. West, and S. subnudibrachtatum, W. & G. S. West. It stands 
nearest to S. levispinum var. tropicum, W. & G. 8. West. (in Ann. Roy. 
