WISCONSIN PHYTOPLANKTON 113 



Adelaide (rrr), Bass (sss), Little Bass (r), Bear (rrr), Blue Gill (ss), Little 

 Butternut (rr), Canteen (rrr), Carson (rrr), Cochrane (rrr), Crooked (ss), 

 Devils (ss). Diamond (ss), Dummy (s), Dunham (rrr), George (rr). Half Moon 

 (rrr), Jag (sss), Jenny (rr). Lake of the Woods (rrr), Lindy (r). Little Doctor 

 (rrr). Long (rrr), Lynx (rr), Meta (ss), Nicaboyne (rr), Oak (r). Pine (rr), 

 Rudolph (r), Sand (rrr), Sanford (rrr). Silver (rrr), Sishebogema (rrr), Speese 

 (rr), Streitor (rrr), Sunday (rr). Tank (ss). Trapper (rrr), Whitney (rrr). 



As I have stated elsewhere (I. c.) this alga seems sufficiently dis- 

 tinct from S. Ophiura Lundell to warrant recognition as a species. 

 It differs from >S', Ophiura in the relative proportions of the cells, 

 smaller size, smaller number of processes, and different ornamenta- 

 tion, both in the apical verrucae and lack of spines on the bases of 

 the semicells. The processes do not have the prolonged lateral ver- 

 rucae of S. Ophiura and lack both the median row of spines and 

 ornamentation of the ventral side. 



var. TETRACERUM (Wollc) G. M. Smith. PL 80, Figs. 19-21. 



Trans. Wis. Acad. Sci., Arts & Lett. 20: 357, pi. 13, figs. 3-5. 1922. 



Staura^trum Ophiura var. tetracerum Wolle, Bull. Torr. Bot. CI. 9: 28, pi. 13, 

 fig. 4. 1882; Desm. U. S. 134, pi. 44, figs. 1-2. 1884; W. & G. S. West, Trans. 

 Linn. Soc. 2nd. Ser. Bot. 5: 268, pi. 18, fig. 16. 1896. 



Cells with the same relative proportions and shape as the type; 

 processes subparallel. Vertical view tetragonal and processes of one 

 semicell alternating with those of the other semicell; processes with 

 spines more prominent, sometimes with spines in the portion near 

 the base bifid and with a median row of spines. (Facultative plank- 

 tont.) 



Cells 32-35 /i, long ; breadth with processes 85-120 fi, without proc- 

 esses 18-20 fi ; breadth at isthmus 10 ft. 



Bass (rrr). Bird (sss), Lindy (cc), Nicaboyne (rr), Sand (rrr), Speese (rr). 



A superficial examination of S. ankyroides Wolle might lead to the 

 conclusion that it is an extremely well developed specimen of this 

 variety. 8. ankyroides differs in the nature of the lateral ornamen- 

 tation of the processes, convergence of the processes and structure of 

 the verrucae on the apices of the semicells. 



49. Staurastrum ankyroides Wolle. 



Bull. Torr. Bot. CI. 11: 14, pi. 44, fig. 4. 1884; Desm. U. S. 137, pi. 51, fig. 4. 

 1884; G. M. Smith, Trans. Wis. Acad. Sci., Arts & Lett. 20: 358, pi. 13, figs. 

 13-15. 1922. 



Cells large, length about three times the breadth (without proc- 

 esses), slightly constricted, sinus a small semicircular depression, 

 isthmus broad; semicells cylindrical, with bases swollen and apex 

 tumid, upper portion of semicell prolonged into four processes, the 

 processes of one semicell alternating with those of the other semicell, 



