94 WISCONSIN PHYTOPLANKTON 



The presence of the characteristic verrucae on the side of the semicells 

 shows, however, that the variety belongs with S. vestitum. In the 

 Wisconsin planliton these lateral verrucae are not so long as those 

 figured by W. & G. S. West, but in all other particulars the two are 

 identical. 



32. Staubastrum anatinum Cooke & Wills. 



Grevillea 9: 92, pi. 139, fig. 6. 1881; W. & G. S. "West, Trans. Eoy. Irish Acad. 

 32: 54, pi. 1, figs. 24-25. 1902; Carter, Ann. of Bot. 34: 307, pi. 14, figs. 19-20. 



1920. 



« 



Cells fairly large, breadth (with processes) one and a half times 

 to twice the length, deeply constricted, sinus acute and with apex 

 acuminate, isthmus narrow ; semicells broadly cyathiform, with the 

 dorsal margin slightly convex and the ventral margin rounded, angles 

 continued in fairly long hollow somewhat attenuated processes that 

 usually terminate in three stout divergent spines, superior and infe- 

 rior margins of processes coarsely serrate and body of processes with 

 a median row of granules, processes subparallel to divergent ; body of 

 semicells with an apical row of 5-7 emarginate verrucae and another 

 lower transverse subapical row of verrucae, lower part of body of 

 semicells smooth. Vertical view triangular, with sides of cell body 

 slightly concave to somewhat convex; angles continued in long 

 straight processes with serrate margins and a single median row of 

 granules, ends trispinate; sides of body of cells with emarginate ver- 

 rucae and central area with similar verrucae (that appear as pairs 

 of granules) just within the lateral margins and connecting with the 

 axial rows of granules of the processes. Chloroplast with a very 

 small central mass and a large broadly lanceolate lobe with a deep 

 incision running to each angle of the cell; pyrenoids usually three, 

 one in each lobe. 



Zygospores unknown. 



Cells 65 [X long with processes, 46 [x long without processes ; breadth 

 with processes 101-113 /x; breadth at isthmus 15.5 ju, (W. & G. S. 

 West). 



Not found in the plankton of Wisconsin lakes. 



var. LONGiBRACHiATUM W. & G. S. West. PL 75, Figs. 11-16. 

 Trans. Eoy. Soc. Edinburgh 41: 504, pi. 7, figs. 8-9. 1905. 



Semicells obversely trapezif orm ; with the apex flattened or slightly 

 concave; body of semicells without the subapical verrucae; processes 

 long, gradually attenuated and with concentric rings of granules at 

 the bases, ends tri- or quadrispinate, processes only slightly divergent. 

 (Euplanktont.) 



Cells 43-68 /* long with processes, 30-35 /a long without processes ; 

 breadth with processes 80-92 [i, without processes 29-37 /x ; breadth 

 at isthmus 10.5-12 fi. 



Adelaide (rr), Crooked (ss), Meta (ss), Nancy (c), Sanford (rrr), Speese (s). 



