THE LIFE OF DEVILS LAKE 61 



"Furthermore, of the species identified, it is worthy of note 

 that with minor differences of measurement, they were all abso- 

 lutely typical, with no indication of any effect of the, in many 

 cases unusual, if not unfavorable, environment." 



The following list is compiled mainly from Dr. Moore's report, 

 the notations being partly from his, and partly from my own data. 



Myxophyceae — Most of the species recorded below are free 

 floating and of general distribution thruout the lake, which may 

 be assumed to be the case for each species, unless it is specifically 

 stated to the contrary. 



Aphanothece castagnei — This species occurs commonly in tow- 

 ings. In the quantitative samples numerous ovoid cells were found 

 which probabi}' belonged here. The colonies soon disintegrate how- 

 ever so that it is difficult of identification. It occurs from the end 

 of May to December, but the records are too scattering to justify 

 any conclusions regarding seasonal distribution. 



Bhahdoderma sigmoid ea has been reported from Main, East 

 and Mission Lakes, and var. minor from Lake P. 



Chroococcus limneticus and minutus. Both of these species 

 are common and occur frequently in the plankton samples. In 

 counting no attempt has been made to differentiate between them. 



It is difficult to draw any conclusions regarding the cycle 

 of Chroococcus from the distribution curves. It occurs in rather 

 large colonies, and one count may show none or few, while another 

 shows a large number. To this fact may be due, in part at least, 

 the more or less zigzag form of the cui-ve, which is especially noticea- 

 ble in 1914. It is rarely very numerous in the collections, which, 

 together with its colonial habit, and the liability of the colonies to 

 disintegrate in preserved material, thus rendering it difficult to 

 identify, tends to obscure the form of the curve. In its seasonal 

 occurrence it is similar to other algae, appearing early in April 

 and disappearing again toward the end of December. Its maximum 

 falls between August 10 and September 15. Its occurrence in the 

 East Lake collections is too scattering to warrant any conclusions 

 regarding its seasonal distribution there (pi. 11 and fig. 18). 



A similar irregularity is evident in Lake Mendota (Birge and 

 Juday, 1922). Chroococcus is present here for about four weeks from 

 the end of May to the end of June, then apparently disappearing 

 until the middle of September, after which it occurs until winter. 

 In 1916 it occurs from the first of May till mid-October, with the 

 exception of a brief interval about August 1, but is not present later 

 in the autumn. 



Two other species of Chroococcus, dispersus and turgidus, occur 

 in Lake P, and the latter has been reported from Main Lake.* 



♦Brannon (1910). 



