152 WISCONSIN PHYTOPLANETON 



The outwardly turned lunate terminal cells, together with the pro- 

 nounced alternate arrangement distinguishes this species from the fore- 

 going. I have given elsewhere (1. c.) the reasons for considering this 

 a distinct species and not a variety of S. obliquus. 



SCENEDESMUS ACUMiNATus (Lagerheim) Chodat. PI. 38, Figs. 1-4. 



Mater, pour la fl. crypt. Suisse I 3 : 211. 1902. 



Selenastrum acuminatum Lagerheim 6'fvers. Kgl. Vet.-Ak. Forh. 39: No. 2: 

 71, pi. 3, figs. 27-30. 1882. 



Coenobia curved, of 4 or 8 (generally 4) cells. All of the cells of a 

 colony arcuate or lunate, fusiform, with the ends gradually tapering 

 to a fine point. Cell wall smooth, without teeth, granulations or spines. 

 (Facultative Planktont). 



Cells 3-7 yu. broad, 30-40 /x, between apices. 



Horse (sss). 



This species should not be confused with Selenastrum acuminatus 

 G. S. West non Lagerheim, a species which I have already discussed 

 in connection with Selenastrum Westii G. M. Smith. 



SCENEDESMUS BEENARDII G. M. Smith. PI. 38, Figs. 5-9. 

 Trans. Wis. Acad. -Sci., Arts, & Lett. 18 2 : 436, pi. 33, figs. 196-208. 1916. 



Colonies of 2-4US cells. Interior cells fusiform, lunate or sigmoid, 

 with acute apices; alternately arranged with apices in contact with 

 apices or median portion of adjacent cells. Terminal cells fusiform to 

 lunate, frequently at an angle to the plane of the coenobe, in contact 

 with the interior cells by the apex only. Cell wall smooth, without 

 terminal spines or teeth. ( Tychoplanktont ?). 



Cells 3-6 p. broad, 8-17 p. long. 



Monona (rrr). 



SCENEDESMUS BIJUGA (Turpin) Lagerheim. PI. 37, Figs. 18-20. 



Kuova Notarisia 1893: 158. 1893. 



Scenedesmus Ujugatus (Turpin) Kiitzing. G. S. West, Brit. Freshw. Algae 

 220, fig. 92c. 1904. 



Coenobes flat, of 2-4-8 cells in a single (rarely subalternate) series. 

 Cells oblong-elliptic to ovoid, with broadly rounded ends. Cell wall 

 smooth, without teeth or spines. (Tychoplanktont). 



Cells 4-7 /x broad, 7-18 /* long. 4-celled colonies 7-18 /i broad, 16-25 



M long- 

 Fowler (rrr), Lindy (rr), Little Rice (2) (rr), Mill (rr), Poplar (rrr), 

 Silver (2) (rr), Streitor (rr), Upper Turtle (rrr), Wolf (rr). 



