36 F. E. FRITSCH. 



RIVULAEIACE^. 



Genus CALOTHRIX Agardh. 



54. CALOTHRIX ANTARCTICA sp. n. 



(PI. III., figs. 161-163.) 



Fills solitariis vel sparse congregatis, flexuosis, usque ad 300 /^ lougis, in stratu 

 Phormidii fragiUs nidulantibus ; vaginis crassis, flavescentibus, indistincte lamellatis, 

 non ocreatis, spatio parvo a trichomatibus sejunctis, ssepe apice diffluentibus ; hetero- 

 cystis basilaribus, solitariis vel rare duabus, plerumque non in vaginis inclusis, ellipticis 

 vel plerumque deplanatis membrana crassa et contentu homogeneo, ssepe effetis ; 

 trichomatibus paulatim apicem versus attenuatis, ut videtur uon in pilum productis, 

 interdum pseudo-ramosis, inter cellulas plus minusve constrictis, dissepimentis indis- 

 tinctis, ssepe granulatis ; cellulis ad basini tricliomatis modice deplanatis, sursum 

 paulo longioribus quam latis, cytoplasmate cum paucis granulis magnis. 



Diam. fil. ad bas. = 10-15 /x; diam. tricb. ad bas. = 6-8 /j. ; diam. fil. in media 

 parte = 8-1 3 /A; diam. trich. in media parte = 5-6 /A ; diam. heterocyst. = W/JL; crass, 

 parietis vaginae = 2 p.. 



Hal, Freshwater pond in cskers upon ice, half-way between Black and 

 Brown Islands, January 3rd, 1903. 



This species was relatively rare, but very distinct owing to the yellow colouration 

 of the sheath ; this is thick, faintly stratified and diffluent at the apex. It does not 

 appear that the trichomes terminate in a hair, although I do not feel sure on this 

 point. The trichomes showed no constriction at the base, but in the upper portions 

 frequently appeared almost moniliform (fig. 1G2). The granulation of the dissepiments 

 (figs. 161, 163) is not a common feature in the genus. 



C. antarctica appears to be rather closely allied to C. fuxca (Kiitz.) Bornet et 

 Flahault, but the latter differs in the bulbous inflation of the base of the filaments, 

 the colourless gelatinous sheaths, the short cells and probably in the production of 

 the trichomes into a long hair. The characters of the sheath also serve to distinguish 

 this species from C. n<tndric<'iisis (Nordst.) Sclmiidle. 



55. CALOTHRIX INTRICATA sp. n. 

 (PI. III., figs. 158-1 GO.) 



Filis in stratu parvo membranaceo dispositis dense flexuoso-contortis et intricatis 

 vel subsolitariis, subbrevibus, ut videtur usque ad 300 fj. longis, ad superficiem 

 Phormidii affixis ; vaginis tcnuibus, distiuctis, achrois, nou ocreatis, plerumque arctis, in 

 basi interdum paulo inflatis ; heterocystis basilaribus, singulis vel pluribus, plerumque 

 in vagiuis inclusis, plus minusve heinisphtericis vel deplanatis, conteutu interdum 



