WISCONSIN PHYTOPLANETON 123 



ing several parietal disciform chloroplasts without pyrenoids. (Tycho- 

 planktont). 



Diam. cells (with processes) 30-40 p. 



Birch Island (rrr), Long (3) (rrr), Sand (2) (rr). 



The specimens from Sand lake were of particular interest since three 

 showed the production of autospores (fig. 6). The chloroplast of old 

 cells are frequently indistinct but they can be seen quite readily in 

 young cells. 



var. POLYFURCATUM G. M. Smith. PI. 26, Fig. 8. 

 Bull. Torr. Bot. Cl. 43: 480, pi. 26, figs. 21-22. 1916. 



Cells tetragonal, flattened or pyramidal; with concave, straight, or 

 slightly convex sides. Processes at angles somewhat tapering, 3-5 times 

 dichotomously branching, the ultimate branchlets with 2-3 minute 

 spines. (Facultative Planktont). 



Diam. cells (without processes) 15-25 /a, (with processes) 35-70 /*. 



Beaverdam (r), Blake (rr), Bone (rr), Clare (rr), Fish (rr), Loon (rr), 

 Muskallonge (rrr), Palmer (r), Pardee (r), Pine Tree (rr), Rice (1) (rr), 

 Shell (rr), Wild Goose (rrr). 



Differing from the typical form in the greater branching of the 

 processes and from T. enorme (Ralfs) Hansg. in the much longer proc- 

 esses. 



TETRAEDRON LIMNETICUM Borge. PI. 27, Figs. 1-3. 



Bet. Not. 1900: 5, pi. 1, fig. 2. 1900; W. & G. S. West, Trans. Roy. Soc. Edin- 

 burgh 41: 507, pi. 6, figs. 10-11. 1905. 



Cells of medium size, tetragonal, pyramidal, the four angles being 

 produced into one or two dichotomous brandlings. Terminal branch- 

 lets with 2-3 short spines. (Euplanktont). 



Diam. cells (with processes) 45-85 //,; diam. base of processes 8-12 /i. 



Chain (rr), Chetek (r), Clear (r), Crawling Stone (rrr), Deer (rr), Diamond 

 (rrr), Island (rr), Kitten (rr), Little Butternut (rr), Little Crooked (rrr), 

 Mud (2) (r), Nancy (rr), Palmer (rr), Pine Tree (rr), Poplar (rr), Spirit 

 (rrr), Squirrel (rr), Wildcat (rr), Wild Goose (rrr), Wolf (rr). 



TETRAEDRON PLANCTONICUM G. M. Smith. PI. 27, Figs. 4-5. 

 Bull. Torr. Bot. Cl. 43: 479, pi. 26, figs. 19-20. 1916. 



Cells medium-sized, four to five sided, sides concave to convex. Angles 

 of cells produced into narrow, once to twice dichotomously branchec 



processes. Ultimate branchlets with 2-3 short spines. Processes ^^Q^ 



in front view, narrow in side or vertical view. (Euplanktont). Xj*/ 



