FRESHWATER ALGM 269 



gully, and of unknown depth. The lake was never seen clear of ice, but round the 

 stones at the margin a little water was found in which Algae occurred. The tem- 

 perature of the water was just over freezing-point. The material consisted of thin 

 papery sheets of Phormidium angustissimum, densely studded with colonies of 

 Pleurococcus dissectus. 



12 Ponds on the slopes of Mt. Erebus 



There were a number of these ponds from whieh^two collections were obtained. 



() March 28, 1908 ; coll. D. Mawson, from ponds rather near the camp. The 

 material consisted of extensive cartilaginous patches of Lyngbya erebi, some 3 to 5 mm. 

 in thickness. Enclosed in this tough stratum were also threads of Lyngbya kiUzingii 

 and Oscillatoria limosa, together with colonies of Pleurococcus dissectus and a few 

 specimens of Tabellaria flocculosa, Cocconema pusitta, Navicula radiosa, and Melosira 

 varians. 



(b) December 31, 1908 ; coll. J. Murray, from ponds about two miles from the 

 camp. The great mass of material consisted of grey papery patches of considerable 

 extent and of 0.5 mm. in thickness, the nature of which was difficult to determine. 

 It is probable that most of it consisted of Leptothrix or other allied filamentous bacteria. 

 Amongst these colourless threads were various sparsely scattered Myxophycese, 

 including Phormidium autumnale and Oscillatoria producta. Colonies of Pleurococcus 

 dissectus occurred on both sides of the grey expanded sheets. 



One tube contained a quantity of Nostoc antarctica.* 



13 High moraines on Mt. Erebus 



Altitude from 300 to 400 feet, and situated about three miles from the camp. 

 Coll. J. Murray. 



() December 1908. Ulothrix implexa, with large numbers of Diatoms, especially 

 Navicula muticopsis. 



(b) January 1909. Quantities of Prasiola antarctica attached to the stones. 

 Amongst it were Gloeocapsa shutUcworthiana and Aphanocapsa montana, the latter 

 covering quite large areas of the stones. 



14 Pond at Cape Barne 



December 12, 1908 ; coll. J. Murray. Two miles south of the camp. Tem- 

 perature of water 54 F. The pond was covered from side to side (from 20 to 30 

 yards) with an unbroken sheet of Myxophycese about 12 mm. in thickness. The mass 

 was kept floating by oxygen bubbles generated by the activity of the Algae. 



This stratum, which was of a totally different character from the blue- green sheets 

 in Blue Lake, Coast Lake, or Deep Lake, consisted of Oscillatoria sancta and Phormidium 

 autumnale. 



* Attached to some half-decayed thalli of this Nostoc were a few small colonies of the fungus Sporodinia asper- 

 gillus Schroet. The specimens, which were carefully compared with British ones, were found to be typical in all 

 respects. This is probably the farthest south record for any member of the Mucorinse. 



