WISCONSIN PHYTOPLA.NKTON 95 



PANDOEINA Bory 1824. 



Colonies always motile, spherical to subspherical, containing 4-8-16- 

 32 cells mutually compressed to form a hollow sphere with a small 

 open space at the center. Colony enclosed by a fairly copious, firm, 

 hyaline, homogeneous, gelatinous envelope. Cells pyriform to angular 

 by mutual compression, with pointed ends toward the center of the 

 colony; biciliate at the flattened distal end, the two cilia lying close 

 together while passing through the colonial envelope and then becom- 

 ing markedly divergent. Chloroplast single, massive, cup-shaped, with 

 one pyrenoid at the base. Eyespot single, generally on distal face of 

 the cell. Cells with a definite wall and two contractile vacuoles at the 

 base of the cilia. 



Asexual reproduction by simultaneous division of all cells of the 

 colony to form autocolonies that are liberated by a gelatinization of the 

 colonial envelope. 



Sexual reproduction by a division of each cell of the colony into 

 16-32 zoogametes. Zoogametes showing indications of heterogamy in 

 the slight difference in size and motility of the pairs that fuse to form 

 the smooth walled zygote. 



PANDORINA MORUM Bory. PI. 16, Figs. 16-17. 



Encyc. meth. hist. nat. de Zoophytes 2: 600. 1824; G. S. West, Brit. Freshw. 

 Algae 193, figs, 76A-76H. 1904. 



Colonies generally 16-celled and as described above. (Facultative 

 Planktont). 



Cells 8-16 /*, broad ; colonies 20-45 p. broad. 



Bear Trap (rrr), Blake (rrr), Camp (rr), Center (cc), Chetac (rr), Chetek 

 (ss), Deer (rrr), Duck (ss), East (rrr), Fowler (rr), Grindstone (s), Hillman 

 (rr), Hooker (s), Kegonsa (sss), Lac Court Oreilles (ss), Lindy (rr), Little 

 Bass (2) (rr), Little Butternut (rr), Little Rice (1) (r), Little Wood (rrr), 

 Long (1) (rrr), Loveless (rr), Lower Nashotah (rr), Lower Nemahbin (rr), 

 Lower Turtle (sss), Mendota (ss), Monona (s), Mud (1) (rrr), Nagawicka 

 (BS), Nicaboyne (r), No Mans (rr), Number One (rr), Oconomowoc (rrr), 

 Okauchee (rrr), Pokegama (3) (r), Prairie (r), Rice (1) (r), St. Croix (rr), 

 Sishebogema (rr), South Turtle (sss), Upper Nashotah (rr), Upper Nemahbin 

 (rr), Upper Turtle (rr), Waubesa (ss), Whitefish (rr), Winnebago (rr). 



EUDORINA Ehrenberg 1832. 



Colonies always motile, spherical or slightly elongate, of 16-32-64 

 cells lying some distance from one another and arranged to form a 

 hollow sphere near the periphery of the homogeneous, hyaline, gelat- 

 inous envelope. Cells spherical, with or without a beak at the point 

 of origin of the two cilia. Cilia parallel while passing through the 



