FRESHWATER ALG^. 29 



35. Lyngbya scotti* sp. n. 

 (PL II., figs. 91-93.) 



Fills angustls, plerumque valde.tortuosls, interdum subrectls, stratum In superficle 

 Phormidii formantlbus ; vaglnls prlmo tenulbus hyallnls, demum modlce Incrassatls 

 extus rugosls cum particulls numerosls adhserentibus, non lamellatis ; tricliomatlbus 

 cum cellula aplcall acuta conlca, non capitatis aut attenuatls, plerumque modlce Inter 

 cellulas constrlctls ; cellulls tarn longls quam latls vel paulo longlorlbus, plerumque 

 cytoplasmate homogeneo, dlssepimentis Indlstinctls, sed interdum cum granulis dense 

 aggregatis in utraque parte dissepimentarum ; calyptra nulla. 



Diam. fil. = 3*4-5 fi; diam. trich. = 2 "6-3 ju.. 



Hah. — Granite Harbour, January 20th, 1902. 



This species should be compared with Lynghya kiltzingi Schmidle, and its 

 variety distincta (Nordst.) Lemm. (= X. suhtilis West). It differs from these forms in 

 the thickened rugose sheath of older filaments, in the acutely conical apical cell, the 

 slight constriction between the cells and the occasional granulation of the dissepiments. 

 The adhesion of small particles to the rough surface of older sheaths is a marked 

 characteristic, as the bulk of the filaments showed it. 



Var. MINOR var. nov. (PI. II., figs. 94-96). 



Fills angustioribus, plerumque valde tortuosis ; vaginis tenuibus hyalinis ; 

 trichomatibus cum cellula apicali acuta conica, interdum paulo attenuatis, modice inter 

 cellulas constrictis ; cellulls tam longis quam latis vel paulo longioribus, contentu 

 homogeneo. 



Diam. fil. = 2 • 5-2 • 7 ju, ; diam. trich. = 1 • 5-1 • 8 /x. 



Hob. — Gap pond, Winter Harbour, February 20th, 1904 (forming a stratum on 

 Phormidium). 



This variety difi"ers chiefly from the type in its smaller dimensions and in the 

 apparent absence of thickening of the sheath in older filaments. The cell-contents 

 were in all cases homogeneous. 



36. Lyngbya lagerheimi. 

 (PI. II., figs. 74-78.) 



Lynglya lagerheimU (Mob.) Gomont, torn, cit., pp. 147-148, PI. IV., figs. 6, 7 (Spirocoleus lafferheimii 

 Mobius, Hedwigia, 1889, p. 312, Tab. 10, figs. 1, 2). 



Diam. fil. = 3-3 "5 /a ; diam. trich. = 2-3 /a. 



Hab. — Freshwater pond in eskers upon ice, halfway between Black Island and 

 Brown Island, January 3rd, 1903. 



* This species is named after Captain Soott, O.V.O., the leader of the British National Antarctic Expedition 

 [and of the British Antarctic Expedition, 1910] . 



