476 SMITH: ALGAE FROM THE LAKES OF WISCONSIN 
PLATE 25, FIG. I3 
DistRiBuTIoNn: plankton, South Turtle Lake. 
The shape of the cells in this species resembles P. Boryanum 
(Turp.) Menegh. but the markings are decidedly different. The 
nearest approach in cell-marking is found in P. araneosum, but 
reticulations in this species are much coarser. 
Pediastrum araneosum (Raciborski) comb. nov. 
Pediastrum angulosum var. araneosum Raciborski, Verh. u. Sitz- 
ungsb. Akad. Wiss. Krakau 20: 101. 1889.. 
DIsTRIBUTION: plankton, Devil’s Lake; along shore, Beaver 
and Muskallonge Lakes. 
This has been regarded as a variety and not a distinct species. 
In my opinion the coarsely reticulate structure of the wall, which 
is correlated with a certain cell-shape, is sufficiently distinctive to 
warrant regarding it as a distinct species and not asa variety of 
some other species. 
Pediastrum araneosum rugulosum (G. S. West) comb. nov. 
Pediastrum Boryanum var. rugulosum G. S. West, Jour. Linn. 
Soc. Bot. 38: 132. pl. 5, f. 22. 1907. 
PLATE 25, FIG. 14 
DIsTRIBUTION: plankton, Meta Lake. 
With the recognition of P. araneosum as a species the variety 
rugulosum very naturally comes under this species instead of 
P. Boryanum. 
Peroniella planctonica sp. nov. 
_ Cells single, gregarious, epiphytic upon cells of, and embedded 
in, mucilaginous envelopes of Sphaerozosma. Cell-shape ovoid- 
pyritorm, with a long delicate stipe. Chromatophore single 
(rarely two), yellow-green in color, without pyrenoid or starch. 
Reproduction by division of cell contents into two to four 
zoospores with one (?) cilium. 
_ Length of cell, without stipe, 9.5-6 y; with stipe, 18-15 #3 
stipes 10-8 X1.2 mu. 
PLATE 25, FIG. 15 
DISTRIBUTION: on Sphaerozosma sp., in plankton of Devil’s 
ake. 
