634 Wisconsin Academy of Sciences^ Arts^ and Letters, 
Ankistrodesmus lacustris (Chod.) Ostenfeld. (Plate 11, fig. 1). 
Hedwigia 46: 384. 1907. 
II. Browns (rr). 
Ankistrodesmus spirale (Turner) Lemmermann. 
Arch. f. Hydrobiol. u. Planktonkde. 4: 176. 1908. 
Eaphidium spirale Turner, Kgl. Sv. Vet.-Ak. Handl. 25: No. 5: 156. pi. 
20. /. 26. 1892. 
AnTcistrodesmus falcatus var. spiralis (Turner) G. S. West, Brit. Preshw. 
Algae 224. 1904. 
II. Silver (rrr). 
Genus CLOSTEEIOPSIS Lemmermann 1898. 
Closteriopsis longissima var. tropica W. & G. S. West. 
Trans. & Proc. Bot. Soc. Edinb. 23: 31. pi. 1, f. 1. 1905. 
Eaphidium longissimum var. tropicum W. & G. S. West, Trans. Linn. 
Soc. Bot. 2nd Ser. 6: 198. 1902. 
The dimensions of the Wisconsin material agree with those 
given in the original description and not with those found in 
the plankton from Scotland. 
I. North Turtle (rr). 
Genus SCHROEDERIA Lemmermann 1898. 
ScHROEDERiA jUDAYi G. M. Smith. 
Bull. Torr. Bot. Cl. 43: 474. pi. 24, figs. 9-11. 1916. 
II. Camp (rrr). 
III. Amicoy (rr). Prairie (rr). 
Genus QUADRIGULA Printz 1915. 
Quadrigula Pfitzeri (Schroder) n. comb. 
AnTcistrodesmus Pfitzeri (Schroder) G. S. West, Brit. Preshw. Algae 224. 
figs. 94G-94H. 1904. 
Printz has recently founded the genus Quadrigula to include 
those AnkisU'odesmus species whose cells lie side by side within 
a common gelatinous envelope. He places Ankistrodesmus 
