352 FRESHWATER AL^ OF LISMORE DISTRICT, 



wandered about the field of view. The trichomes pale blue-green, 

 transparent, attenuate, and curved at the tips; dissepiments dis- 

 tinct, sometimes smooth, sometimes granulate. A great variety 

 of apices were noted, the prevailing types, liowever, being 

 rounded, capitate, or with depressed conical calyptra. 



Phormidium lucidum (Ag ) Hansg. (PI. xlvi., f.5.) 

 Fila distincta, libera; vaginis baud agglutinatis. Trichomata 

 dilutissime {aeruginosa, ad genicula constrict a, cellulis altioribus 

 plerumque dissepimentis incipientibus instructis. 

 Trich. diam. 8-1 0; cell. alt. 2 3 /x. 

 Lismore(213) Cum sequenti intermixtum. 



Var. AMCENUM(Kutz.) mihi. (PI. xlvi., f.6.) 



1. Fila distincta, libera; vaginis baud agglutinatis. Tricho- 

 mata dilutissime {aeruginosa semper paene hyalina, ad genicula non 

 constricta, apicibus conicis vel late-rotundatis, cellulis angustis, 

 dissepimentis conspicuis baud granulatis. 



Trich. diam. 5-6; cell. alt. 1 J-3 fx, interdum ad 1 /x approx. 

 Lismore (213). 



2. Fila libera. Trichomata saturate aeruginosa, apicibus rotund- 

 atis subtruncatis, dissepimentis interdum minute granulatis, ssepe 

 septis inconspicuis alternantibus. Cetera ut in f. precedente. 



Trich. diam 8-10 (rarius 11); cell. diam. 3-4 /x. 

 Lismore (213). 



3. Fila glabra libera. Trichomata dilute aeruginosa, ad geni- 

 cula quam levissime constricta, apicibus rotundatis conicis, dis- 

 sepimentis validis non autem granulatis. 



Trich. diam. 6; cell. diam. 2-4, vulgo 2 /x. 



Lismore (232). 



Amphitrix amoena Kiitzing, (pro parte) Tab. phyc i., p 45, T.79, 

 f.l {sec. Gomont). Phorm. ambiguum Gomont, Monog. d Oscill., 

 p. 178, PI. v., f.iO. This is a form of Ph. lucidum without con- 

 stricted joints. Not only are the two forms otherwise exactly 

 alike in general characteristics, but, in sample No. 2 13, I find 

 them intermixed; and, in No.232, an intermediate form in which 

 the constriction is very faint, represented only by a minute 



