134 BIOLOGY OF THE RICHMOND KIVER, 



Diam. fil. 2 J; cell. alt. 2-6; spora immatura sphserica diam. 4; 

 spora matura oblonga, long. 8, lat. 4 /x. 

 Lismore(13). 



Var. CHLORINA, n.var. 



Trichomata pallide luteo-viridia; diam. fil. 1 /x; cell. alt. 3-6 /x. 



Casino (14). 



Phonnidium tenue occurred sparsely in a considerable number 

 of samples, and in some quantity in Nos.2 and 26, but in no case 

 was it in the Phormiduim state. This is also my experience 

 with gatherings made near Sydney, where I found it only once 

 in the agglutinated condition, viz., in an open drain in Park Rd., 

 Auburn (No. 48, N.H.S.). I am of the opinion that the PAor- 

 miduim state is merely an accidental condition brought about by 

 exposure of a stratum to the air and sun. A filament with a 

 spore, as given in Pl.vi., f.l3c, was noted also at Auburn (Nov. 

 16th, 1909). The spherical cell is not a heterocyst, but an 

 immature spore. 



Phormidium fragile (Menegh.) Gomont. (PL vi., f.l4). 



Diam. fil. 2-3i; cell. alt. 2-3 /x. 



Lismore (12). 



Generally found sparingly in mixed gatherings as short fila- 

 ments, here and around Sydney. Meneghini made it an Ana- 

 bjena, and here it was found in company with A. oscUlarioides 

 var. cylindracea (PI. vi., f.l) with cells of the same shape, diam. 

 4-6 /x. I should not be surprised if it turned out to be the 

 transition-stage between the two genera. I have never found it 

 either in the Phormiduim condition. Gomont makes it a marine 

 form. 



Genus Spirulina Turpin. 

 Spirulina major Kiitz. (PI. vi., f.l5). 

 Spira diam. 4; anfr. 4-6 inter se distant.; trich. diam. H /x. 

 Lismore (12), loose filaments. 



Spira diam. 4; anfr. 2-3 inter se distant.; trich. diam. 1^/x. 

 Coraki, river-brink (27), mucous stratum. 



