conspicuous in late summer until in September 

 the combined species reached 9, 000 per liter 

 at station 48. 



Gomphosphaeria aponina Kdtzing. (R). 



G omphosphaeria lacustris Chodat. (R). Small 



quantities at several western stations in Septem- 

 ber. 



Lyn^bya aerugineo-caerulea (Kiltzing) Gomont. 

 (R). Probably a chance wanderer. 



Lyngbya birgei G. M. Smith. (R). Throughout the 

 summer. 



Merismopedia elegans A. Braun. (R). 



M erismopedia punctata Meyen. (C). This species 

 and the following in western area totaled 2, 500 

 colonies per liter at station 48 in September. 



Merismopedia tenuissima Lemmermann. (C). 

 Western stations in September. A variety of 

 this species with cells remote &om each other 

 was very abundant at station 48. The cells of 

 this variety were 2 microns in diameter and oc- 

 curred in pairs, the rows of cells being 10 

 microns apart. 



Microcystis aeruginosa Ktftzing. (C). August and 

 September, particularly in the western area. 



Microcystis aeruginosa var. major (Wittrock) G. M. 

 Smith. (T). Should perhaps be included under 

 the species. 



Microcysti s flos -aquae (Wittrock) Kirchner. (R). 



Microcysti s incerta Lemmermann. (C). Widespread. 



Microcysti s sp. ?. (C). August. The description 

 of M. holsatica var. minor Lemmermann seems 

 to fit the organism, but it may be a bacterium 

 rather than a blue -green alga. 



Oscillatoria sp. (R). 



Protozoa 



Acanthocystis chaetophora Schrank. (R). 



Amoeba sp. (R). Probably due to the method of 

 preserving the samples these forms were often 

 overlooked. 



Cothurnia sp. ?. (R). Occurring on Melosira; 

 figured by Vorce (1882). 



Difflugia cratera Leidy. (C). Widespread. 



Difflugia globulosa Duj. (C). 



Difflugia sp. Cylindrical form occurring with the 

 other species. 



Epistylis plicatilis Ehrenberg? (T). Western area at 

 surface. The colonies were floating free, ap- 

 parently having broken away from their 

 substrata. 



Monosiga ovata S. Kent. (R). Found occasionally 

 on diatoms. 



Sphaerophrya sp. (R). 



Vorticella rh abdosty loides Kellicott. (C). Com- 

 monly found attached to Anaba ena fl os-aquae, 

 reaching 1, 000 per liter in August when its 

 host was abundant in the eastern part of the lake. 



Rotifera 



A napus ovalis Bergendal. Abundant only at several 

 stations east from Long Point, reaching 200 per 

 liter there. Not found in the western area. 



Anuraea aculeata Ehrenberg. (R). 



Anuraea cochlearis Gosse. Ubiquitous but not very 

 numerous, except at several eastern stations 

 where the maximum numbers were estimated at 

 about 100 per liter. 



Apsilus sp. (T). 



Ascomorpha sp. (T). 



Asplanchna priodonta Gosse. (T). 



Asplanchnopus milticeps Schrank? (R). Shallow 

 water only. 



Conochilus unicornis Rousselet. Widespread but not 

 abundant except in shallow water east from Long 

 Point Bay, In July 1928 it occurred in swarms 

 near shore at several stations. 



Gastropus sp. (R). 



Haningia eupoda Gosse. (R). 



Lecane luna MuUer? (R). 



Monostyla cornuta Ehrenberg. (R). 



Monostyla quadridentata Ehrenberg. (R). 



Notholca longispina Kellicott. (R). Widespread. 



P loesoma truncatum Levander. (R). 



Ploesoma hudsoni Imhof. (R). 



Polyarthra platyptera Ehrenberg. (R). Occurring 

 throughout the lake, 1-10 per liter at the sur- 

 face and bottom. 



Synchaeta stylata Wierzejski. (T). Eastern area. 



Triarthra longiseta Ehrenberg. (R). 



Trochosphaera sp. (R). Only in shallow water in 

 1928. 



127 



