THE LIFE OF DEVILS LAKE 67 



Botryococcus braunii. "Abundantly present in one towing. 

 Doubtfully present in two other towings. " Also in neighboring 

 fresh waters. 



Ankistrodesmus falcatus. Found infrequently in plancton col- 

 lections from Main Lake. 



Characium hookeri. Occurs abundantly as an epiphyte on 

 Crustacea and filamentous algae. Found frequently but irregularly 

 in the plancton samples at all seasons. Its irregularity renders it 

 difficult to draw any definite conclusions as to its seasonal distribu- 

 tion. Numerous detached cells are found in the collections but 

 normally it is probably always epiphytic, mainly on Crustacea. 



"Apparently the first record of this species in America." 



Coelastrum microporum. "Rare in towings." 



DictyosphaeriiDii. This, in common with Characium and 

 Oocystis, is the most characteristic of the green algae in the plancton. 

 It readily disintegrates in preserved material so that the records are 

 incomplete. Especially is this true for most of the 1914 collections, 

 which could not be counted until 1919. No attempt has been made 

 therefore to plot a distribution curve for this year. The records for 

 1913, which are complete except for the period from June 24 to 

 August 1, show practically none in winter, with a rather uniform 

 rise from none on May 1 to a maximum about October 10, and a 

 return to zero by the end of December. 



In 1923 Dictyosphaerium appeared on May 12 and gradually 

 but slowly increased up to July 23 when the collecting ended 

 (pl. 15). 



Both ehrenbergianum & pulchellum occur in the complex. 



Nephrocytium naegelii. "Occurring rather frequently in tow- 

 ings. ' ' 



Eudorina elegans. A rare species reported only from Main 

 Lake. 



Oocystis is one of the characteristic genera, but very irregular in 

 its presence in the plancton samples. In 1913 a small maximum 

 occurred about September 1, while in 1914 there Vvas a very marked 

 rise on September 14, when the collections were ended (pl. 13). 



Judging from the diagrams of Birge and Juday (1922) Oocystis 

 is rather more regular in its occurrence in Lake ]\Iendota than in 

 Devils Lake, but here too marked irregularities occur. 



It is represented in the complex by five species, crassa, lacustris, 

 naeglii, pusilla and solitaria, of which the latter is the most numer- 

 ous. 



Scencdesnms hijugatus and quadricauda typiciis. "Both species 

 rather common in towings, also associated with filamentous algae 

 along shore," and of occasional occurrence in the plancton samples. 



Zoochorella conductrix. "In Stentor from towings." 



