630 Wisconsin Academy of Sciences, Arts, and Letters, 
OOCYSTIS GLOEOCYSTIFORMIS Borge. 
Botaniska Studier tillagnade P. E. Kjellmann 23. pi. 1, /. 1. 1906. 
III. Lac Court Oreilles (sss). 
OocYSTis NOVAE-SEMLiAE var. MAXIMA W. & G. S. West. 
Jour. Eoy. Mier. Soc. 1894: 13. pi. 2, f. 25. 
III. Duck (r). 
Oocystis eremosphaeria sp. nov. 
Cells ovoid, 2-1% times as long as broad, solitary or in fam¬ 
ilies of 2-4. Chloroplasts numerous, lens shaped, each contain¬ 
ing a single pyrenoid. Cell wall thick, with a conspicuous 
nodule at each pole. (Plates 14, figs. 8-9). 
Cells 45-35 y long, 31-23 y wide. Families up to 100 
x60 y. 
The large size of the individual cells together with the num¬ 
erous chloroplasts at once distinguishes this from all other 
species. Playfair (Proc. Linn. Soc. N. S. Wales 41: 106-147. 
1916) has recently attempted to show that Eremosphaeria viridis 
de Bary is merely a polymorphic condition of Oocystis and not 
a distinct species. The species which is described above is much 
more like E. viridis than any other Oocystis species but the cells 
always have the ovid shape and polar nodule so characteristic of 
Oocystis, There is, in my opinion, no evidence for regarding 
E. viridis as a growth form of Oocystis. 
III. Beaverdam (rr). Shell (sss). 
Oocystis natans var. major var. nov. 
Cells 38-31 X 25-16 /x. Families up to 120 x 90 y. (plate 
15, figs. 6-7). 
This variety has the typical star shaped chloroplast contain¬ 
ing a single pyrenoid but the cells are much larger. 
III. Birch (sss), Chetac (s). 
Genus MICRACTINIUM Fresenius 1858 
Micractinium pusillum Fresenius. 
Abh. Senckenb. Naturf. Ges. 2: 236, pi. 11, -figs. 46-49. 1858; G. M. Smith. 
Bull. Torr. Bot. Cl. 43: 479. pi. 25, f. 18. 1916. 
II. Hooker (rr). 
III. Chetek (rr). Island (rrr), Pokegama (rr). Prairie (rr). 
