72 THE LIFE OF DEVILS LAKE 



Mastigloio. Two species of Mastigloia, elliptica and smithii, 

 occur in the complex, of which the former is common and widely 

 distributed; while of the latter there is but one record (Main Lake 

 12/29/15), altho Professor Elmore reports it from a fresh water 

 lake in the vicinity. The genus appears sporadically in the plancton 

 collections. 



Scolioplcura peisonis. In his "Diatoms of Nebraska" Elmore 

 (1921) gives Devils Lake as his only record for this species. It is 

 not mentioned by Schonfeldt (1913), while Professor Elmore 

 informs me that Van Heurck (1896) records it as marine. Elmore's 

 only record from Devils Lake is Minnewaukan Bay, 7/20/15. 



Navicula. No attempt has been made to ditferentiate the 

 various species of Navicula in the plancton samples. The genus 

 occurs irregularly in the collections thruout the year. It has a 

 fairly well marked maximum in May-June and two other rather 

 indefinite maxima in July-August and October-November. Tl 

 frequently appears in large numbers in the shore collections* 

 while absent or rare in the others. This irregularity renders it diffi- 

 cult to draw any very definite conclusion regarding its seasonal 

 distribution. 



Notwithstanding the irregularity of its occurrence it is, as 

 might be expected, the richest in species, and one of the richest 

 in numbers of the genera inhabiting the lake complex. The follow- 

 ing species have been identified by Professor Elmore : ambigua, 

 anglica, brebissonii, cincta, crucicula, cryptocephala, hinigarica, 

 iridis, lacustris, lanceolata, fulva, gastrum, major, minnewan- 

 konensis, oblonga, parva, pygmaea, rostrata, scandinavica, sculpta, 

 sphaerophora and sub-capitata. 



AinplLora. Of the two species of Amphora present in the com- 

 plex ovalis is common and widely distributed, occurring in fresh 

 and alkaline waters alike; while proteus is much rarer, being 

 reported by Elmore only in Main and Mission Lakes. 



Amphora occurs occasionally in tlie plancton collections, but 

 no attempt has been made to chart its seasonal distribution. 



CjjniheUa. Four species of Cymbella occur in the complex 

 (aequalis, cistula, parva and pusilla), of which the latter is the 

 most common and widely distributed. Parva occurs in fresh waters 

 as well as in Mission Lake, while ae(|ualis is reported only from 

 Lake P. 



The genus occurs sporadically in the plancton collections from 

 the first of May to the middle of November, but the data are insuf- 

 ficient for drawing any conclusions regarding its seasonal distri- 

 bution. ' 



— — — 



*Soo p. 70. 



