BY G. I. PLAYFAIR. 351 



Cf. Lemmermann, Engl. Bot. Jahrb., 34, 1905, p. 620. Syn., 

 Lynghya suhtilis West, Alg. Lake Dist., p. 29, PI, x., f.58 ; L. 

 Martensiana (3 distincta Nord., Alg. Sandvich., p.4; L. circum- 

 creta G. S. West, Third Tanganyika Exp., p. 174, PI. 9, f.7. Tri- 

 chomes pale blue, with homogeneous but generally opalescent 

 protoplasm, so that the dissepiments are barely visible; occasion- 

 ally, however, with translucent protoplasm, when the septa are 

 distinct The same occurs in 0. splendida. The ceUs are square 

 or a little shorter than the diameter, the sheath very delicate, 

 filaments often spirally twisted, apices truncately-rounded. 

 Lynghya circumcreta G. S. West, I.e., is a plankton-form of the 

 species, the coiling of the filaments being a plank ton^phenomenon 

 of not infrequent occurrence (cf. Melosira granulata var. circinalis 

 Playf., Syd. Water-Supply, p. 536), and not of any specific value. 

 It should be noted as confirmatory that this form was obtained 

 from the same two localities as L. Kiltzingii var. distincta, I.e., 

 pars. 308. 309, at the same time of year. 



Genus Phormidium Kiitz. 

 Phormidium uncinatum (Ag.) Gomont. (PI. xlvi., 14.) 



l.Fila distincta, libera, vaginis baud agglutinatis. Dissepi- 

 menta plerumque baud granulata. 



Trich. diam. 7-8, cell. alt. 2-4, vulgo 3-4 /x. 

 Lismore(212). 



2. Fila distincta, libera, vaginis baud agglutinatis. Septa 

 granulata. 



Trich. diam. 8, cell. alt. 4-5 fx. 

 Lismore(230). 



3. Fila distincta, libera, vaginis baud agglutinatis. Septa ssepe 

 granulata. Trichomata omnia apicibus capitatis. 



Trich. diam. 8, cell. alt. 4-6 /Jt, 



Lismore (252). 



Oscill. uncinata Ag., Ph. uncinatum (Ag.) Gomont, Monog. d. 

 Oscill., p. 184, PI. v., f.21, 22. Three, fine, mucous strata of this 

 plant were obtained, not one of which, as stated above, was in 

 the PAormic?mm-condition. The filaments were free, and 



