110 THE LIFE OF DEVILS LAKE 



Marshia albuqerqensis has hitherto been reported only from 

 New Mexico** (Herrick and Turner 1895) and Colorado (Dodds, 

 1920). Our present knowledge regarding its distribution is too 

 limited to consider it in attempting to determine the zonal position 

 of the lake or the origin of its fauna. 



Laophonte calamorum. This species, recently described by 

 Willej^ (1923 a), is evidently widely distributed in both fresh 

 and alkaline waters, having been found thus far in the Quill 

 Lakes, Saskatchewan, De^dls Lake, N. D. and Lake St. John, 

 Quebec. 



The origin of the fauna and flora of Devils Lake must be 

 traced back to the days of the old glacial lake Minnewaukan when 

 the latter was a part of the Mississippi drainage basin. At this 

 time it was possible for both northern and southern forms to 

 have entered directly, and without any carriage by birds or any 

 air blown dust, etc. Later, with the loss of this connection and 

 the establishment of one into Lake Agassiz, only northern ele- 

 ments could enter directly, and this condition remained after the 

 retreat of Lake Agassiz and while Devils Lake was draining 

 through the Sheyenne River into the Red River. The loss of this 

 outlet has been comparatively recent. Since then additions to the 

 fauna and flora must have been thru outside agencies. 



The foregoing facts indicate then that the fauna and flora of 

 Devils Lake are in general widespread in their distribution and un- 

 doubtedly have come from manj" sources. 



At present the life of the lake is distinctly fresh water in 

 character with, however, a considerable admixture of brackish water 

 forms. The species are for the most part cosmopolitan in their 

 distribution. Of those types with restricted distribution it is dif- 

 ficult to say whether northern or southern ones predominate, until 

 we have fuller information regarding the distribution of aquatic 

 animals and plants. 



The fauna and flora, moreover, are not static, but are changing 

 from year to year with the changing character of the various lakes 

 in the complex. Thus, as already pointed out,* Filinia lougiseta 

 has apparently disappeared from Main Lake with the gradual in- 

 crease in concentration of its water. Similarly the Crustacea, with 

 the exception of Marshia, have apparently disappeared from East 

 and Mission Lakes in recent years, while the latter, on the contrary, 

 has increased in numbers (1922). 



No careful study has been made of these changes, but the above 

 data are sufficient to demonstrate clearly the great changes that are 

 taking place. 



**In liis puMieation Ilprrick apparently does not mention the locality. Marsh, 

 howpvpr, in Warrl &. Wliipplc (1918. p. 780) kivos it as New Mexico. 

 *See p. 86. 



