WISCONSIN PHYTOPLANKTON 135 



Tree (rr), Poor Farm (rr), Poplar (rr), Rock (1) (rr), Tenderfoot (rr), 

 White Ash (rr). 



var. ACICULARIS (A. Braun) G. S. West. 

 Brit. Freshw. Algae 223, figs. 94e-94c. 1904. 



Cells usually solitary, straight or slightly curved, apices acutely at- 

 tenuated. Chloroplast single, parietal, with or without a pyrenoid. 

 Cells 2.5-4 p. broad, 36-65 n long. 



Beaverdam (rr), Little Bass (1) (rrr), Mendota (rr), Rice (1) (rr), Wau- 

 besa (rrr). 



var. TUMIDUS (W. & G. S. West) G. S. West. PI. 32, Fig. 2. 

 Brit. Freshw. Algae 224, fig. 94o. 1904. 



Cells solitary or in small aggregates, straight or curved, inflated at 

 the middle and with acute apices. Chloroplast single, parietal, with 

 or without pyrenoids. (Tychoplanktont). 



Cells 4.5-6.5 p. broad ; 61-73 ^ long. 



Devils (1) (rrr), Mendota (rr). 



var. MIRABILIS (W. & G. S. West) G. S. West. PI. 32, Figs. 3-5. 

 Brit. Freshw. Algae 224, fig. 94s. 1904. 



Cells solitary, straight, lunate, or sigmoid; with acute apices; much 

 longer and narrower than the typical form. Chloroplast single, com- 

 monly fragmented by large vacuoles in the cytoplasm; without pyre- 

 noids. ( Euplanktont ) . 



Cells 2-3.5 //, broad ; up to 150 ^ long. 



Bear (3) (rr), Bryer (rr), Chain (sss), Crab (rrr), Devils (1) (sss), 

 Devils (2) (rr), Dummy (rr), High (rr), Horseshoe (1) (rr), Reserve (rr), 

 Squirrel (rr), Travis (rrr), Whitefish (rr). 



ANKISTRODESMUS SPIRALIS (Turner) Lemmermann. PI. 32, Figs. 6-7. 



Arch. f. Hydrobiol. u. Planktonkde. 4: 176. 1908. 



Raphidium spirale Turner, Kgl. Sv. Vet.-Ak. Handl. 25, No. 5: 156, pi. 20, 

 fig. 26. 1892. 



Ankistrodesmus falcatus var. spiralis (Turner) G. S. West, Brit. Freshw. 

 Algae 224. 1904. 



Cells acicular, attenuated to acute apices ; in colonies of four or eight 

 and spirally twisted around one another in the middle of the cell but 

 with the extremities free. Chloroplast single, completely filling the 

 cell; without a pyrenoid (?). (Tychoplanktont). 



