504 NEW AND UARE FKESIIWATKR ALG.'E, 



almost liyaliiie, witli cells so strictly rectangular and so closely 

 adpressed that the trichoine has the appearance of an Oscillatoria\ 

 the slight constriction at the joints, a mere nick at the edge, is 

 discernible only with the yV obj. (often the dissepiments also): 

 contents homogeneous or finely granular. Heterocysts narrow , 

 strictly cylindrical. Gonidia one or two on either side of a 

 heterocyst, narrow, cylindrical; contents bright blue, granular. 



Var. CONSTRICTA, n.var. (PL liv., f.lO). 



Forma gonidiis in medio constrictis. Cell. diam. o, alt. (S-lO; 

 heteroc^^st. diam. 4, alt. 11; gonid. diam. 4-6, alt. 19-21/x. 



Lismore (350). 



A form with rather short gonidia somewhat constricted in the- 

 middle. 



Anab^na variabilis var. cylindracea, n.var. (PI. liv., f. 11-1 3). 



Trichomata Hexuosa, dilute cterulea, ad genicula constricta; 

 cellulis stricte rectangularibus, disjunctis, apicibus truncatis; 

 cytoplasmate minute granulato ; heterocystidibus oblongis vel 

 oblongo-cylindraceis, apicibus rotundatis; gonidiis doliformibus, 

 quadratis vel oblongis, disjunctis, apicibus truncatis. 



Cell. diam. 3, alt. 4-6; heterocyst. diam. 4-5, alt. 7^-10^; gonid. 

 diam. 6, alt. 7-lOJ/x. Lismore (316). 



Easily recognised as A. variahilis by its catenate gonidia remote 

 from the heterocysts, differing from the type, however, in its 

 rectangular cells. All parts of the trichome also seem to be 

 slightly more slender than usual. The gonidia were perhaps 

 immature, and would probably become oblong with rounded ends. 



Anab^na oscillarioides var. crassa, n.var. (PL liv., f.l4). 

 Forma cellulis crassioribus, globosis (e divisione oblongis vel 

 oblongo-constrictis) ; cytoplasmate teruginoso ; heterocystidibus 

 interdum minoribus, sphgericis; gonidiis oblongis, apicibus rotund- 

 atis, cytoplasmate seruginoso granulato. 



(1). Cell. diam. 6-8; heterocyst. 4; gonid. diam. 9, alt. 22-23/x. 



Lismore (298). 

 (2). Cell. diam. 8-9|; heterocyst. 8; gonid. diam. 12, alt. 25/x. 

 Lismore (337). 



