THE LIFE OF DEVILS LAKE 59 



material was in poor shape, however, when counted, and the form 

 of the curve may be somewhat obscured as a result. In the records 

 from December 3, 1922, to July 23, 1923, Micrococcus was disap- 

 pearing from the plancton, when the records began. During the 

 winter it was absent from most of the collections, tho present in 

 every series in the shore samples. It increased rapidly in May and 

 June to a large and well marked maximum about the middle of the 

 month, falling off rapidly until the end of the collection period. 



Much of the material included under Micrococcus may be 

 Clathrocj^stis, which occurs commonly in the Devils Lake plancton, 

 and which in preserved material "might closely resemble the coccus 

 form of the bacterium and I doubt if it would be possible to separate 

 the two".* 



Micrococcus, while present in East Lake, had for the most part 

 deteriorated when the counts were made. 



Sarcina is much less abundant than either of the preceding, 

 and the records in general are too scattering to admit of anj^ con- 

 clusions reg'arding seasonal distribution other than that a marked 

 decrease occurs in winter, with a corresponding increase in summer 

 and autumn. Its distribution is approximately similar to that of 

 the two preceding, altho it is conspicuously less abundant in spring. 

 It is possible that some of it may have been included with Micro- 

 coccus. 



The quantitative analyses covering the period from June 27 to 

 August 9, 1916, and including 27 samples were designed to show 

 rather the spatial than the temporal distribution of the bacteria in the 

 Devils Lake complex. They showed quite clearly, as might be expected, 

 the much greater abundance of bacteria in situations where there was 

 a greater amount of decaying matter, such as the shore and bottom, 

 compared with the surface, or the lake some distance out from 

 shore, and the heads of shallow bays as compared with the middle 

 of the lake. Especially numerous were the bacteria near the mouth 

 of the Devils Lake sewer at the head of Creel Bay. The B coli group 

 were not limited to the former situations, but were widely distribut- 

 ed thruout the lake. 



These results are of interest when compared with the organic 

 analyses, in a majority of which (about 2 to 1) the organic con- 

 tent is higher at the bottom of the lake than at the surface. 



The distribution of the bacteria in the various lakes of the com- 

 plex has not been studied thoroly enough to warrant any definite 

 conclusions. 



During the summer of 1916 the Mauvaise Coulee was flowing into 

 Devils Lake carrying with it large numbers of bacteria. This un- 



•From a letter to the writer from Dr. Geo. T. Moore, who Identified the 

 Devils Lake algae. 



