68 THE LIFE OF DEVILS LAKE 



Actinastrum hantzschii. Reported from Main Lake and fresh 

 waters. 



Pediastrum angulosum and horyanum. "Both species rather 

 frequent in towings. " No attempt has been made to differentiate 

 them in the counting of the plancton collections, and their occur- 

 rence here is too irregular to warrant the construction of a distribu- 

 tion curve. Pediastrum apj)ears sporadically from April to Decem- 

 ber. 



The following attached forms are characteristic of the shore 

 and Ruppia zones. Of these Cladophora is the most characteristic, 

 altho Entermorpha is very common in several scattered localities. 



Microspora loefgrenii. The cell wall of this species may be 

 occasionally .006 mm. thick, which is perhaps an adaptation to its 

 saline environment, altho without a change in permeability mere thick- 

 ness would hardly be adequate to prevent plasmolytic action of the 

 water on the cell contents. The increase in thickness moreover only 

 occurs in some specimens, which is a further argument against its 

 adaptive character. 



Ulothrix zonaia. "With Cladophora along shore." 



Enteromorpha. "Although Enteromorpha is ordinarily re- 

 garded as a marine form, E. prolifera has been reported from sev- 

 eral fresh water lakes in the west." Intestinalis( ?), prolifera and 

 an indeterminate species occur in the complex. 



Protoderma viride. "On stones along shores." 



Stigeoclonium nanum. "Attached to Cladophora and associat- 

 ed with Enteromorpha." 



Cladophora. The most characteristic littoral genus in all the 

 lakes of the complex. Both kuetzingiana and an indeterminate 

 species occur. 



Rhizoclonium hieroglyph icum has been found in Lakes P and N. 



Vaucheria sp. One record from Main Lake (6/24/15). 



Oedogonium sp. Taken in Lake P. only. 

 DIATOMACEAE 



The diatoms of Devils Lake have been studied by Profesor C. J 

 Elmore of William Jewell College, both at the lake and in collec- 

 tions sent to him from time to time. They are the most numerous 

 in species, altho not greatest in numbers of any class of plants in 

 the lake. Serving as food for many species of animals they play a 

 very important part in the biology of the lake. They include a 

 total of 80 species,* 46 of which are fresh water types with two 

 doubtful forms additional ;18 inhabit both fresh and brackish water; 

 1 fresh, brackish or marine ; 4 marine or brackish, while four are 

 brackish and four marine types only. There is one new species 

 (Navicula minnewaukonensis). 



•Including one siibspecios (Navicula orptocephala venpta). 



