128 BIOLOGY OF THE RICHMOND RIVER, 



Forma oircinalis, n.f. 

 Fila circinalia, diam. 5; cell, sphaericis, ovalis vel truncato- 

 globosis; heterocyst. sphaericis, diam. 5; ovalibus, long. 7, lat. 6 /x. 

 Lismore(3). Cum var. cylindraced 



Var. CYLINDRACEA, ii.var. (PI. vi., f.l). 



Fila diam. 4-6 (7), apicibus attenuatis; cellulis quadratis vel 

 cylindraceis, alt. 2-8, plerumque 4-6, endochroma homogenea vel 

 vacuolata, Heterocystidibus sphaericis, diam. 6 ; oblongis vel 

 ovalis, long. 6-8, lat. 5-7; aut cylindraceis, long. 6-10, lat. 5-6. 

 Sporis oblongis vel cylindraceis, long. 12-16, lat. 5-10 /x. 



Lismore(2rt, 26, 12, 16). 



Differs from var. stenosjxtra Born, et Flah., only in the shape of 

 the cells and the breadth of the spores, the latter, except when 

 immature, having the dimensions of the type. The dimensions 

 given above for the spores ai-e the greatest noted in this district; 

 round Sydney, I have observed spores up to 34 x 11 /x, very rarely, 

 however. A torulose form of this variety, all dimensions agree- 

 ing, was also observed there (at Rookwood). Atiahoina Volzii 

 Lemm., Dr. Volz gas. siisswass., p. 153, T.xi., f.4, 5, 20, is a form 

 of this species distinguishable from var. cylindracea only by its 

 barrel-shaped spores. I have found it at Canley Vale in com- 

 pany with the type (in fruit;. A var. Novce Zelandice Lemm., 

 Reise n.d. Pacific, p. 355, has very narrow cylindrical spores 3 /x 

 broad and 16/x long, but the cells are spherical and smaller, 

 diam. 2-3 /x. 



Genus Nodularia Mertens. 

 NoDULARiA SPUMIGENA Mertons. (PL vi., f.2). 

 Fila diam. 8; cell. veg. alt. 2-4, plerumque 2; heterocyst. de- 

 pressis, diam. 8, alt. 4-8; sporis immaturis diam. 8, alt. 4, maturis 

 diam. 8-9, alt. 6-7 /x. 



Coraki, river-bank near Commercial Hotel (29) 



The sheath was evident. There is, I think, no doubt that the 



appearance generally referred to in descriptions of the Lyngbyece 



as " trichomata ad genicula constricta " is due to the formation 



of a cellulose ring on the sheath, opposite the junction of the 



