I'UKSinVATER A I/;.*]. 



3t 



39. PHORMIDIUM TEXUE. 



Phormidiinn tmue (Mune.uh.) (ium., tmn. fit., p. Hit), PI. IV., figs. 23-2.*). 



Diarri. fil. = 1 *5-2 ^. 



Hull. Freshwater pond in ice oft' Black Island, McMnrdo Strait, December 3 1st, 

 1902 (forming a thin stratum overgrown liy \i.n//if,t,'i,i 1,'m'ttllt:! and species of 

 Oscillatoria) ; Gap pond, Winter Harbour, December 15th, 1903. 



The cell-contents were occasionally slightly granular. 



40. PHOKMIDIUM FRAGILE. 

 Phormidium fragile (Mencgh.) Gom., torn, n't., pp. li;:;-ii;4, PI. IV., tigs. 13-1">. 



Diani. trich. = 1 5-1 8 p. ; long. cell. = t ' 5-2 /x. 



Iluli. Freshwater pond in eskers upon ice, half-wa\' between Black and 

 Brown Islands, January 3rd, 1903; Gap pond, Winter Harbour; growing in and 

 through ice in pond among the eskers which border the shore (.if the Western mainland, 

 December 2nd, 1902. 



41. PHORMIDIUM FRKUDTM sp. n. 

 (PI. I., fig. 52.) 



Strato, ut videtur, tenui, membranaceo, colore? (ut videtur serugineo); filis 

 plerumque pins minusve tortuosis et iutricatis, iuterdum parallelis ; vaginis mucosis, 

 in muco hyaliuo difrlueutibus ; trichomatibus inter cellulas distinete constrictis, saepc 

 fere moniliformibus, apice non attenuate, cellula apicali rotundata; ccllulis tarn longis 

 ijuani latis vel ad duplo longioribns, cvtoplasmate dilute serugineo, homogeneo, rare 

 granulato ; dissepimentis plerumque cum granulo magno distincto ssepe deplanato in 

 utraijuc parte, intcrdum modo in altera parte, vel sine granulis ; ralyptra nulla. 



Diani. trich. = 0'8-l - 2^ (interdnm ad I '5ju.). 



llali. 1 kill brick-coloured ice, situated in long level line, as though in situation 

 of former water-level, four feet above frozen water-course through " Penknife ice," 

 Mc.Murdo Bay, September 13th, 1902. 



This form, which presumably grows on (lie surface of Ihc ice, was only present 

 in minute pieces, so that the general colour uf the stratum cannot definitely be staled. 

 It belongs to Gomont's first section Moniliformia, but differs from all other species of 

 that section in the frequent presence of granules at the dissepiments ; although 

 occasionally wanting, the granules were always pre.-enl mi ihc majority of the septa in 

 each filament. The grannies were generally more or less flattened against the 

 dissepiments, which gives the trichomes a rather characteristic aspect (cf. the uppermost 

 filament in fig. 52). 



Except for the shortness of the cells and the granulated dissepiments the species 

 resembles P. angustissimum W. and G. S. West. It also comes close to P. fragile 



VOL. VI. 





' 





