THE TJFE OF DEVILS LAKE 93 



Diaphanosoma hrachiuruin. I'rcseiil, in East and Mission Lakes 

 in 1911, and one record from Main Lake 10/2/17. 



Marshia albuquerquensis. Of occasional occurrence. !My rec- 

 ords show its presence in Main, East, Mission, A and Lakes, 

 as well as in fresh water. Present in Main Lake occasionally froni 

 July 20 to Sept. 6. 



There are but three previous records of this species, that of 

 Herrick (1895), Dodds (1920) and Willey (1923a).* Doubtless 

 the examination of other brackish lakes in the western United States 

 would reveal its presence elsewhere. In the Devils Lake complex 

 it occupies a wide variety of habitats, showing its adaptability to 

 widely different conditions. It occurs but rarely in Devils Lake 

 proper, but recenth' has developed in considerable number.s in 

 East and Mission Lakes. 



Marshia appears occasionally in the plancton catches from 

 East Lake, but too infrequently to warrant very definite conclu- 

 sions regarding its seasonal distribution. IM}^ earliest record is 

 May 5 and my latest August 2. 



Laophonte calamorum. I have but one record of this species 

 for the Devils Lake complex, from Lake C, Sept. 1917. It has re- 

 cently been reported by Willey {1923a) as a new species from the 

 Quill Lakes, Saskatchewan, which are quite similar in their chemical 

 character to those of the Devils Lake complex, and in Lake St. John, 

 Quebec. According to Willey the other species of the Laophontidae 

 are strictly marine, but this species has adapted itself to both 

 brackish and fresh water. 



Hyallela azteca. A common form, but not of sufficient num 

 bers to appear, other than occasionally, in the plancton. It occurs 

 in all zones and at all depths of the Main Lake, and is widely dis- 

 tributed thruout the complex, and neighboring fresh waters. It is 

 notably phototropic in its reactions, but, as with other zooplankton, 

 does not appear to show any relation to light in its distribution. 

 Stereotropism appears to be an important factor in its distribution, 

 for it is frequently found crawling over submerged objects, such 

 as timbers. It is more or less of a scavenger, and is found in large 

 numbers on the bodies of dead birds. In their moist feathers it 

 will live for several days after removal from the water. I have 

 observed it copulating as early as April 15, while the lake was still 

 frozen. 



Cyprls pellucida. This species has been definitely determined 

 from Main Lake onh', but doubtless occurs in other parts of the 

 complex also. 



Ostraeods occur but rarely- in the plancton catches; consequent- 

 ly no attempt has been made to follow their seasonal distribution. 



*From Devils Lake complex. 



