BY G. I, PLAYFAIR. 133 



Genus Lyngbya Ag. 

 Lyngbya Lismorensis, n.sp. (PI. vi., f.ll). 



Stratum fusco-olivaceum. Fila semper recta, margine glabra, 

 pallide griseo-viridia, translucentia; apicibus attenuatis, interdum 

 calyptra instructis. Cellulae apicales coniese vel rotundato- 

 conicse, rarius capitatse, plerumque ad extremes membrana in- 

 crassata. Vaginae achroas tenuissimae. Trichomata ad genicula 

 hand constricta, dissepimentis crassis, plerumque pellucidis 

 glabris, interdum minute granulatis. Cytoplasma liomogeneum 

 translucens. 



Diam. fil. 7-9, sub calyptra 4; cell. alt. 4-8, saspe 6 /x. 



Lismore, on curbstone near Commercial Hotel(26), river-water. 



Diam. fil. 6-8, cell. alt. 4-8 /x. 



Lismore, river (12, 13). 



Yar. NIGRA, n.var. (PI. vi., f.l2). 



Fila obscure griseo-cjerulea vel obscure griseo-viridia; apicibus 

 saepe late-rotundatis. Cetera ut in forma typica. 



Lismore, horse-trough near Gov. Savings Bank (30, 34). 



The characteristic points of L. Lismorensis are the pale (or, in 

 var. nigra, dark) grey colour of the filaments, flashed with pale 

 green or pale blue, this latter point especially noticeable when 

 the filaments are slightly out of focus. Also the quadrate cells, 

 with their broad pellucid dissepiments, and the finer and fainter 

 septa which sometimes alternate with the others, and are often 

 to be noted just starting from the margins. The tips of the 

 filaments, when fully formed, are capitate or calyptrate; but such 

 are very rare, and conical tips, with the calyptra in process of 

 formation, are more common. The broadly rounded ends often 

 seen, are merely the result of broken filaments, and are not 

 typical. Separated on a watchglass, in the mass the filaments 

 are of a dull olive-green. 



Genus Phormidium Kiitz 

 Phokmidium tenue (Menegh.) Gomont. (PL vi., f.l3). 

 Diam. fil. 1-2; cell, alt. 2-6, plerumque 3-4, raro 8-10 /x. 

 Lismore (2, 26, 12, 13, 18); Coraki, river-brink, with Spirulina 

 (27), and Nodularia (29). 



