86 THE LIFE OF DEVILS LAKE 



Filinia longiseta. In September and early October 1909 this 

 species was of occasional occurrence in the planeton collections from 

 the main lake. Since with increase in salt concentration of the 

 water above 1% it appears to be absent there, but was present in 

 two collections from Minnewankan Bay in 1916, when this Bay was 

 reduced about 2/3 in salinity and greatly increased in area, due 

 to the influx from the Mauvaise Coulee, it appears to be unable to 

 adapt itself to as great concentration of salts as several other species 

 in the complex. 



It has also been reported in Spring Lake. It is in general very 

 rare in the complex but in the Minnewaukan Bay samples of 1916 

 Mr. Harry K. Harring of the United States National Museum re- 

 ports it as "abundant" and "common" in two collections. My last; 

 record from the Main Lake is May 17, 1912. 



Pedalia fennica (pi. 20, 21). Abundant and widely distributed 

 in the complex and in fresh waters. It is evidently readily adapta- 

 ble to a great variety of habitats. 



Its distribution curve for Main Ijake shows that in 1911 three 

 rather poorly defined maxima occurred, one about mid-July, one in 

 early and one in late August. In 1912 a distinct maximum oc- 

 curred about May 25. The records for this year, altho incom- 

 plete, suggest also another smaller one about the end of August. 

 In 1913 a small maximum occurred the last of May, and three 

 well marked maxima from August to October (8/12/20, 9/3/10, 

 and 9/29-10/6), altho the latter consists chiefly of a great develop- 

 ment at shore on the last date, which may have been due to a 

 swarm and not indicate a time maximum at all. 



Occurs rarely in winter, but is in active reproduction very early 

 in spring, gravid females having been taken as early as April 8 (9) 

 when the lake was still frozen. 



In a letter to the writer of July 17, 1912, Mr. Kousselet says, 

 "It is remarkable that Pedalia fennica should be found in ac- 

 tive reproductive stage - - so early in the year (May 17) 

 . . . in Europe Pedalion mirum is a summer form and is hardly 

 ever seen before June." 



Asplanchna silvestrii. During summer Asplanchna occurs 

 rather frequently in the planeton samples and occasionally in con- 

 siderable numbers (100 pr. 1. 0.6 m. depth, 6/24/12). It is too 

 erratic however to justify any attempt at an analysis of its seasonal 

 distribution. It usually occurs in numbers of 50 pr. 1. or less. It 

 appears rather suddenly in considerable numbers, about the end 

 of June, disappearing again in September or early October. 

 My earliest record for Main Lake is 4/20/12 and the latest 

 10/15/10. Present also in Mission Lake (1914), in Spring Lake, in 

 Lakes A, and C. and in fresh water lakes of the complex. Numerous 

 in a collection from Creel Bay (6/24/10) in which several males were 



