468 Wisconsin Academy of Sciences, Arts, and Letters. 
Yar. spicatus (West and West) nov. comb. (PL XXVII: 
Fig. 51; PI. XXXI: Figs. 141-146.) 
S. spicatus. West and West, 1898, p. 335. West and West, 
1901B, p. 120. G. S. West, 1904B, p. 220; Fig. 92L. Volk, 1905, 
p. 65. Brunnthaler, 1913, pp. 166, 170; Fig. 9. Chodat, 1913, 
p. 25. 
“S. cellulis plerumque binis, ellipticis, diametro circiter 
2-plo longioribus, supra marginem exteriori serie spinarum 
brevium 6-7 praeditis. Long. cell. 7.5-9 p. Lat. cell. 4 p. 
Long. spin. 2-2.5 g.” 
The mature cells of the form which I have isolated in 
pure culture "from the Yahara River below Lake Monona 
(Wisconsin) have practically the same dimensions as those 
given by West and West, being 3.5 x 7 to 4 x 10 p with spines 
2-2.5 p long. The two-celled colonies in my cultures have 
the five to seven spines arranged as the authors describe 
(Figs. 143, 146), but four-celled colonies occur much more 
frequently than do the two-celled ones. The poles of the 
middle cells, in the four-celled colonies, each bear one or 
two spines, 2-3 p long (Figs. 141, 142) and the outer margin 
of the terminal cells bears five to seven spines. The fact 
that four-celled colonies have spines on the middle cells as 
well as on the sides of the outer cells is sufficient warranty for 
regarding this as a variety of S. abundans. 
Var. brevicauda now var. (PI. XXX: Figs. 126-132.) 
Dimens. cell. 5 x 2.5, 6 x 2.5, 6x3, 8x4, 8x5 p. Long, 
acul. 1.5-3 p. 
Resembling the variety spicatus but different from it in 
the number of spines, the outer cells never having more 
than five spines. The cells in my pure cultures also are 
smaller than the variety spicatus. 
Var. asymmetrica (Schroder) nov. comb. (PI. XXVII: 
Figs. 45-46.) 
S. quadricauda var. asymmetrica. Schroder, 1897C, p. 45; PI. 
II, Fig. 5. Garbini, 1899B, p. 275. Schmidle, 1900A, p. (111). 
Migula, 1907, p. 655; PI. XXXV (L), Fig. 5. Chodat, 1913, p. 22. 
