578 Annals of tJie South African Museum. 



2. Anabaena inaequalis (Kurtz.), Bornet et Flahault, op. ci£.,p. 231. 

 Sample ■> (?, epiphytic on Vaucheria), '■'>'■'< (?, epiphytic on Clado- 



phora). 



A form with bundles of straight parallel filaments (diam. up to 

 8/a), frequently enclosed within a common sheath whose edge was 

 often granular; apparently always epiphytic. 



3. Anabaena catenula (Kuetz.), Bornet et Flahault, op. at., p. 232. 

 Sum pic 32. 



Lat. cell, veget., Gjx; lat. heterocyst, 1-lh \x.-, lat. spor., 8-9 /*; 

 long, spor., 15 [j.. 



4. Anabaena oblonga, De Wildeman, Algues rapp. par M. J. Massart 

 d'un voyage aiu Ind. neerland., Ann. Jard. Buitenzorg, 1 Suppl., 

 1897, p. 50; Algues Buitenzorg, 1900, p. 27; Forti, op. cit, p. 447. 

 (Fig. 37. a-c). 



Sample 6 (rare, among Cylindrospermum alatosporum, n. sp.) 



Diam. cell, veget., .3"5-4 «,; diam. heterocyst, 5"5 /x; long, hetero- 

 cyst., 8-10 p.; lat. spor., 6 l: ; long, spor., 9-13'5 /u. 



The specimens agree well with DeWildeman's diagnosis, except for the 

 fact that the spore-membrane shows no yellow colour. De Wildeman 

 does not describe the shape of the spores, although lie gives dimensions 

 which are quite in accordance with those recorded above. The spores 

 were cylindrical with flat or slightly rounded ends, and were not 

 uncommonly a little contracted in the middle, after the manner of 

 those of A. catenula, Bornet et Flahault (Fig. 37, a, b) ; they were 

 always remote from the heterocysts. The apical cell of the trichome 

 is more or less pointed (Fig. 37, c). This species undoubtedly conies 

 near to A. inaequalis, Bornet et Flahault, but differs from it in the 

 shape of the heterocysts and of the spores. 



{Note. — Specimens of Anabaena, that were not determinable, were 

 also encountered in samples 2. 3, 4, 7, 8, 10, 29, 30, 50, 51). 



Genus CYLINDROSPERMUM Kttetzino. 



1. Cylindrospermum alatosporum, n. sp. (Fig. 37, d-h.) 

 Stratum tenue, laete aeruginosum, limo affixum ; trichomatibus 

 dense aggregatis, valde elongatis, subparallelis vel saepe flexuosis, ad 

 dissepimenta levissime constrictis ; cellulis tarn longis quam latis vel 

 ad duplo longioribus, quadratis vel rectangularibus ; polis truncatis, 

 contentu aeruginoso plus minus granuloso ; cellula apicali rotundata ; 

 heterocystis ellipticis vel subconicis, saepe segmentis membranae 

 numerosis circumdatis ; sporis plerumque singulis, interdum pluribus, 



