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New or interesting algae from the lakes of Wisconsin 
GILBERT MORGAN SMITH 
(WITH PLATES 24-26) 
The present paper embodies various notes that have accu- 
mulated in a study of the algae of Wisconsin lakes for the Wisconsin 
Natural History and Geological Survey. Although a systematic 
account of the algae found has been prepared, it has been thought 
advisable to publish descriptions of the new species and notes on 
certain other species at this time. 
Chaetosphaeridium ovalis sp. nov. 
Thallus of five to twenty cells, epiphytic upon filamentous 
Chlorophyceae, gelatinous sheath indistinct. Cells ovoid, with 
two parietal chloroplasts each containing a pyrenoid. Sheath at 
the base of setae conspicuous. 
Cells 22-20 uw long, 15-13 uw wide; length of setae about 125 yp; 
basal sheath of setae 15 X3 x. 
PLATE 24, FIG. I 
DIsTRIBUTION: along shore, Marion Lake. 
The two species of the genus that are generally recognized, 
C. globosum (Nords.) Klebh. and C. Pringsheimit Klebh., are found 
also in the lakes of the state. C. ovalis resembles C. Pringsheimu 
forma conferta Klebh. in the arrangement of its cells, but the cell- 
shape is quite different. This species also differs from the others 
since it is the only one which regularly has more than a single chro- 
matophore, while the basal sheath of the bristle is also more. con- 
spicuous in this than in the other species. 
Oocystis panduriformis minor var. nov. 
Cells 35-30 » long; maximal diameter 15-12 u, median di- 
ameter I4—II yp. 
PLATE 24, FIG. 2 
DistriBuTion: plankton, Star Lake. 
471 
