WISCONSIN PHYTOPLANKTON 47 



EHABDODERMA LINEAEE Schmidle and Lauterborn. PI. 6, Fig. 4. 

 Ber. d. D. Bot. Ges. 18: 148, pi. 6, figs. 8-11. 1900. 



Specific characters as those of the genus. (Euplanktont). 

 Cells 2-3 IL broad, 6-12 p. long. 



Sand (2) (rrr), Whitefish (rr). 



This genus is closely related to Gloeothece, the chief difference being 

 a lack of individual sheaths around the cells. 



DACTYLOCOCCOPSIS Hansgirg 1888. 



Colonies microscopic, free-floating or lying among other algae; em- 

 bedded in a copious, hyaline, homogeneous, acicular to fusiform, gela- 

 tinous envelope. Cells elongate, acicular and with pointed ends; 

 straight arcuate, sigmoid, or spirally twisted around one another. In- 

 dividual cell sheaths confluent with colonial envelope. Cell contents 

 homogeneous or with the color bearing area localized in a definite part 

 of the cell ; grey to bright blue-green in color. 



Reproduction by vegetative division of cells at right angles to their 

 long axes. 



KEY TO THE SPECIES. 



Length of cells never more than sixteen times the breadth, 



cells frequently bent D. RAPHIDIOIDKS 



Length of cells at least twenty times the breadth, cells al- 

 ways straight D. ACICULABIS 



DACTYLOCOCCOPSIS RHAPHIDIOIDES Hansgirg. PI. 6, Fig. 7. 



Prodr. d. Algenfl. v. Bohmen 139, fig. 49A. 1892; Lemmermann, Kryptogamenfl. 

 d. Mark Brandenburg 3, Algen 1: 50. 1907. 



Colonies containing 2-8 or more cells. Cells fusiform ; straight, arcu- 

 ate or sigmoid ; frequently in pairs with one end rounded and the other 

 pointed. Colonies enclosed by a copious, hyaline, homogeneous en- 

 velope. Cell contents homogeneous, pale blue-green. (Facultative 

 Planktont). 



Cells 1-3 /A broad, 5-25 p long. 



Deer (sss), Long (2) (rrr), Mercer (rr), Reserve (rr), Rice (1) (rr). 



Hansgirg gives eight as the maximal number of cells found in the 

 colony but I have observed colonies in which there are as many as a 



