Cymbella ventricosa KUtzing. (R). 



Diatoma elongatum (Lyngbye) Agardh. (C). Common 

 at certain stations. Reached 6, 700 colonies per 

 liter (10 cells to a colony) in June 1929 at station 

 19. Decreased in July and was never so abundant 

 again. 



Diatoma vulgare Bory. (T). 



Fragilaria capucina Desmazieres. (C). Less abun- 

 dant than F. crotonensis with which it occurs. 



Fragilaria crotonensi s Kitton. (VA). In September 

 in the western area reaching 68, 000 per liter. 

 Present elsewhere in almost every sample. 



Fragilaria virescens Ralfs. (R). 



Gyrosigma attenuatum (Kiitzing) Cleve. (R). 



Melosira arenaria Moore. (R). 



Melosira crenulata (Ehrenberg) KUtzing. (A). Occur- 

 ring with M. granulata . 



Melosira granulata (Ehrenberg) Ralfs. (A). In June 

 the combined species M. crenulata and M. 

 granulata, totalled 64, 000 per liter at station 

 46. Summer decline followed by an increase to 

 60, 000 per liter at a number of stations in Sep- 

 tember. 



Nayicula rhyncocephala Kiitzing. (R). 



Navicula sp. (T). Not true planktonts. 



Nitzschia linearis (Agardh. ) W. Smith. (R). 



Nitzschia vermicularis KUtzing) Hantzsch. (R). 



Rhizosolenia eriensis H. L. Smith. Abundant at cer- 

 tain stations in both the surface and bottom sam- 

 ples, especially in the eastern area. In June 

 1929 there were about 300 per liter in the waters 

 of the Buffalo area. C. M. Vorce (1880) states 

 that the species is most abundant in the winter 

 months and appears to favor cold water. 



Stephanodiscus niagarae Ehrenberg. (C). Reached 

 2, 500 per Liter in the western area in September. 

 Vorce (1880) found S tephanodiscus most abun- 

 dant in ihe winter and early spring. The present 

 author has found it the most common diatom in 

 the city water supply of Buffalo in the winter 

 months. 



Surirella biseriata de Brebisson. (C). About 100 per 

 liter in surface samples in September. 



Surirella ovalis Meneghini. (R). 



Synedra longissima W. Smith. (R). 



Synedra pulchella (Ralfs) KUtzing. (R). Occurred with 

 S. longissima . 



Synedra ulna ( Nitzsch. ) Ehrenberg. (C). Widespread. 



T abellaria fenestrata (Lyngb. ) KUtzing. (A). Maximum 

 of 2, 500 per liter occurred in September in the 

 western part of the lake where the other filamentous 

 diatoms were also very numerous. The average 



for T abellaria in September was estimated at 

 about 500 per liter and its zig-zag chains oc- 

 curred in every gathering made during this 

 month. 

 Tabellaria flocculosa KUtzing. (R). Western area 

 in September. 



Dinophyceae 



Ceratium hirundineUa Milller. (C). Rare in June, 

 except in Long Point Bay, but increasing in 

 late summer to 500-800 per liter in September. 



Peridinium sp. (R). 



Euglena sp. (R), 



Euglenineae 



Myxophyceae 



Anabaena circinalis ( KUtzing) Rabenhorst. (R). 

 Locally numerous at some western stations in 

 August. 



Anabaena flos-aquae (Lyngb.) de Brebisson (C). 

 Following the decline in numbers of Aphani- 

 zomenon, Anabaena flos-aquae increased rapid - 

 ly during August when 3, 000 colonies per liter 

 were found in the waters at both ends of the lake. 

 Fewer were taken in the middle area. In Sep- 

 tember the species declined. 



Anabaena lemmermanni P. Richter. (R). 



Aphanizomenon flos-aquae Ralfs. (A). Reached 

 4, 000 per liter in the west in June. Declined 

 in July and was replaced by other blue -green 

 algae, Anabaena , Coelosphaerium , etc. 



Aphanocapsa elachista var. conferta W. and G.S. 

 West. (R), 



Aphanocapsa elachista var. planctonica G.M.Smith. 

 (C). Rather widespread in small quantities 

 throughout the lake in August and September. 



Aphanothece clathiata var. brevis Nordstedt. (T). 



Aphanothece nidulans P. Richter. (T). At surface; 

 frequently found as traces in the surface tows. 



Chroococcus dlspersus (von Keissler) Lemmermann. (R). 



Chroococcus limneticus Lemmermann. (C). Oc- 

 curred in small quantities in August and to a 

 greater degree in September. 



Coelosphaerium kuetzingianum Naegeli. (Q. 



Coelosphaerium naegeUanum linger. (C). More 



abundant than the preceding species with which it 

 was usually associated. Following the decline of 

 Aphanizomenon in July, Coelosphaerium became 



126 



