Smith—Monograph of Scenedesmus. 
449 
quently alternate are not rare. The arrangement of the 
cells in a linear series is never found in this variety. The 
dimensions of the cells agree very well with those given by 
Wille. 
9. S. curvatus. Bohlin. (PL XXVI: Figs. 17-18.) 
Bohlin, 1897, p. 23; PI. I, Figs. 41-44, 52. Chodat, 1901, p. 
1309. Marsson, 1901 A, p. 115. Chodat, 1902, p. 212; Figs. 
132A-132F. Volk, 1905, p. 64. Fritsch, 1906, p. 205. Migula, 
1907, p. 658; PI. XXXV (L), Fig. 3. Brunnthaler, 1913, pp. 169, 
171; Fig. 22. 
“Sc. coenobiis e 8 (nonnumquam 4) cellulis in seriem duas, 
alternantes conjunctis, ad basim brevitor cohaerentibus, 
interstitia latitudini cellularum similia formantibus. Serie 
cellularum in orbem tres partes peripheriae circuli efficientem 
curvata. Cellulis subcylindricis, obtusis, in centrum coenobii 
leniter curvatis, chlorophoris singulo, pyrenoida singula in- 
cludentis. Dimens. cell. 12-30 x 4-10 ju.” 
The cell arrangement forming about three-fourths of a 
cylinder, gives a very characteristic appearance to the 
coenobe, while the angular compression where the cells join 
one another makes a further difference between S . curvatus 
and S. bijuga var. alternans (Reinsch) Borge. 
GEOGRAPHICAL DISTRIBUTION 
England (Fritsch, 1906). Germany (Marsson, 1901A, Volk, 
1905). Paraguay (Bohlin, 1897). Switzerland (Chodat, 1901, 
1902). 
10. S. arcuatus. Lemm. (PI. XXVI: Figs. 19-20; PL 
XXIX: Figs. 94-98; Pl. XXX: Figs. 99-100.) 
Lemmermann, 1899, p. 112; Pl. I, Figs. 2-4. de Toni et Forti, 
1899A, p. 179. de Toni et Forti, 1899B, p. 791. West and West, 
1900, p. 298. Lemmermann, 1904A, p. 158. Lemmermann, 
1905B, p. 158, 162. Reinhardt, 1905, p. 26. Lemmermann, 
1907B, p. 411. Migula, 1907, p. 658. Lemmermann, 1908A, p. 
167. Marsson, 1908B, p. 116. Gugliemetti, 1910, p. 32. Lem¬ 
mermann, 1910A, pp. 294, 298. Marsson, 1911, pp. 263, 286. 
Brunnthaler, 1913, pp. 169, 171; Fig. 23. 
5. bijugatus var. arcuatus. Lemmermann, 1898B, p. 159. 
Lemmermann in Marsson, 1899, p. 172. Schmidle, 1900, p. (111). 
West and West, 1906B, p. 105; PL X, Figs. 12-14. 
