108 OOCYSTIS AND EREMOSPH^RA, 



swampy grass-lands, periodically dry, where rainwater collects; 

 23, 45, 57, 60, 70, 74, 84, SS, 91, 92, 95, 106, 1 U, 128, 146, from 

 pond-edges and weeds in pools; 112 from weeds in creek-pools; 

 4, 13, 58, 93, from Sphagnum-bog. Plankton: 63, 65, 100, filter- 

 sci'eens, Sydney Water-supply; 136, from several gallons of lake- 

 water passed through filter-papers; 272, 273, 274, 281, from 

 weed-beds in river. 



When we consider, in the light of this classification, the habitats 

 from which the various species and forms have been obtained, a 

 very interesting and instructive fact becomes apparent. Certain 

 species and their forms are found here almost exclusively in pools 

 (or river), while others are just as strongly devoted to swamps. 

 Thus, all the species in my notes, from 0. Ndgelii to 0. suhhex- 

 af/oiia, viz. : — 0. Nagelii, 0. Nov(t Semlue, 0. siibmarina, 0. n'assa, 

 0. lacustris, 0. jyarva, 0. nodulosa, 0. solitaria, 0. rotula, 0. snb- 

 sphcm'ica, 0. apiculata, and 0. suhhexagona, with almost all their 

 forms, are pond-, river-, and plankton-types; whilst 0. Nordstedt- 

 iana, 0. Choda/A, 0. aitstraliensis, 0. jmndrcriformis, and 0. oiialis, 

 along with all forms of Eremosphri^ra,* are swamp-dwellers. The 

 constant association of this group of Oocysfis-iorms with Ere/mo- 

 sjihrcra is noteworthy, as there are good reasons for- believing 

 them to be closely connected biologically. 



Of Emyiospho'ra viridis in the Biitish Isles, G. S. West, Brit. 

 Frw. Alga?, p.229, remarks that it is found "more especially in 

 Sphagnum-bogs." This, however, is not the case here. Out of 

 seven gatherings from the only piece of Sphagnum-bog that I 

 know, the type alone is present in three, and var. ovalis by itself 

 in two others, in all cases very sjiarsely distributed indeed. 



Scope. — The object of this paper is threefold: — (l)to give an 

 account of all forms of Oocystis and Eremo»phcera met with in 

 New South Wales; (2) to direct attention to the polymorphism 

 of Eremosphcera, and to its connection with Oocystis; (3) to supply 

 the original descriptions and figures, as far as possible, of all 

 published species and forms of the two genera. 



* Out of 46 records of Er-emospho'ra, only 5 are out of pools, and, even 

 in these eases, its cells are very little in evidence. 



