138 WISCONSIN PHYTOPLANKTON 



of granules. Apical processes close together and more elongate than 

 the type. (Facultative planktont.) 



Zygospores spherical, with longer spines than the type (Gut- 

 winski). 



Cells 22-27 [x long with apical processes, 17.5-20 /x long without 

 processes ; breadth 30-35 [i ; breadth at isthmus 10-12 //, ; length of 

 apical processes 2-3 jn. 



Beaverdam (rr), Devils (rr), Horseshoe (rrr), Eazorback (rrr), Shell (rrr), 

 Fish (rrr). 



2. Sphaerozosma exiguum Turner. PI. 86, Fig. 21. 

 Kgl. Sv. Vet.-Ak. Handl. 25, No. 5: 141, pi 18, fig. 16. 1893. 



Cells small, length and breadth about equal, sinus fairly deep, 

 broad and with a rounded apex, isthmus relatively narrow ; semicells 

 transversely elliptic, with the ventral margin more rounded than the 

 dorsal, lateral margins very broadly rounded and without granules ; 

 apical processes simple granules that lie some distance from each 

 other. Chloroplasts axial and with one pyrenoid. (Tychoplank- 

 tont.) 



Zygospores unknown. 



Cells 14 IX long, 12.5 fx broad ; isthmus 6.5 [x broad. 



Carson (rr), Jenny (rrr). 



Except for the pair of granules between adjacent cells this looks 

 very much like a small specimen of Spondylosium planum (Wolle) 

 W. & G. S. West. 



3. Sphaerozosma excavata Ralfs. PI. 86, Figs. 17-18. 



Ann. & Mag. of Nat. Hist. 16: 15, pi. 3, figs. 8A-8C. 1845; Brit. Desm. 67, pi. 6, 

 figs. 2A-2G. 1848. 



Cells small, length slightly greater than the breadth, fairly deeply 

 constricted, sinus a broad semicircular depression, isthmus elongate 

 and fairly narrow ; semicells oblong-elliptic, with the ventral margins 

 more rounded than the dorsal, apex flattened, with the apical proc- 

 esses reduced to simple granules that lie some distance apart ; lateral 

 margins flattened, with 2-3 small granules, at times with one or two 

 granules within the margins. Vertical view oblong-elliptic, with 

 rounded poles. Lateral view of semicells subcircular, with the sides 

 compressed. Chloroplast axial and with one pyrenoid. (Facultative 

 planktont). 



Zygospores spherical, with smooth walls (Ralfs). 



Cells 14 IX long, 11-12.5 /x broad ; breadth at isthmus 6.5 ju. ; thick- 

 ness 5 [x. 



Diamond (rrr). Horseshoe (r), Lac Court Oreilles (rrr), Little Doctor (rrr). 

 Two Sisters (rr). 



