Smith—Monograph of Scenedesmus. 
459 
357. Lemmermann, 1908E, p. 405. Schneider, 1908, p. 46. Borge, 
1909, p. 16. Lemmermann, 1910A, p. 294. Borge, 1911, p. 204. 
Marsson, 1911, p. 286. Brunnthaler, 1913, p. 168; Fig. 15. 
S. hystrix var. brasiliensis. Chodat, 1902, p. 215. 
S. acutiformis var. spinuliferum. West and West, 1902, p. 182; 
PI. IV, Figs. 46-49. Lemmermann, 1904C, p. 159. 
S. hystrix forma brasiliensis. Volk, 1905, p. 65. Migula, 1907, 
p. 657. Selk, 1907, pp. 7, 73, 79, 91, 103, 108. 
S. hystrix forma brasiliensis cohaerens. Volk, 1905, p. 65. 
Selk, 1907, p. 6. 
S. acutiformis var. brasiliensis. West and West, 1905, p. 270; 
PI. I, Figs. 8-9. West and West, 1907, p. 229. G. S. West, 1907, 
p. 138. G. S. West, 1909C, p. 245. West and West, 1909B, p. 184. 
S. acutiformis var. bicaudatus. Gugliemetti, 1910, p. 31. 
“Sc. coenobis e cellulis quaternis (vel octonis) in seriem 
simplicem, rectam conjunctis, oblongis, obtusis; membrana 
in utroque polo denticulis parvis instructis, costus tenerrimis 
quaternis, quarum binis lateraliter dispositis. 
“Dimens. colon. 4-cellularum. 8-11, 14-16, 19-19, 22-23, 
20-24 yr 
Although this form has not been obtained in culture I 
have observed it in nature. Ridges on the sides of the cell 
are the distinguishing character which separates this species 
from S. denticulatus Lag. Since cultures of other species of 
Scenedesmus made in connection with this study show that 
ridges are a character which remain constant in all descend¬ 
ants of a single mother cell, it is reasonable to assume that 
the lateral ridges are also constant on the cell walls of S. 
brasiliensis. 
The identity of this form has not been disputed but there 
has been some question as to its systematic position. Chodat 
enlarged the S. hystrix of Lagerheim to include all forms 
with lateral ridges, while West and West have placed several 
laterally ridged forms among the varieties of S. acutiformis 
Schroder. Of the two the latter is the much more logical, 
but since lateral ridges are found in quite differently shaped 
cells, it is best not to group them as varieties but rather as 
separate species. 
GEOGRAPHICAL DISTRIBUTION 
EUROPE. Germany (Lemmermann, 1900A, 1901B, 1902, 1906, 
1907B, 1908E, 1899; Marsson, 1899, 1911; Schmidle, 1900. 
Schneider, 1908; Schorler, 1907; Selk, 1907; Volk, 1903, 1905;) 
