276 



Mr. W. H. Pearsall. 



Phytoplanhton. — While no data are available for an accurate numerical 

 comparison of the phytoplankton of these lakes, the investigations of 

 W. and G. S. "West* have already drawn attention to the fact that differences 

 in its composition exist. The Wests' investigations included all the larger 

 lakes except Coniston and Esthwaite. In addition, they described the 

 periodicity of three lakes — Wastwater, Ennerdale and Windermere.f The 

 following Table gives the maximum abundance of a few conspicuous plankton 



Table VII. — Maximum Kecorded Abundance of Principal Plankton Algte.* 



Wastwater 



Ennerdale 



Buttermere 

 Crummock 



Desmids dt. {Staurasfrum jacuUferiim, West.) ; Peridiniiim WiUei, 

 Huit. Kaas and Sphserocystis Schroeteri, Chodat. ab. ; B,Mzosolenia 

 morsa, West., and Tahellaria spp., fr. 



Desmids dt. (Staurastrum jacuUferum, liinatum Tar. planctonicum, 

 West, longispinum, Bail.) ; Sphserocystis Schrceteri and Peridinum 

 Willei ab. ; Mhizosolenia morsa fr. 



Desmids dt, {St. jacuUferum) ; P. Willei, S. Schroeteri and Dinohryon 

 cylindrieum, Imhof . ab. ; Tabellaria spp. fr. 



Desmids {Stanrastrum annatimim, C. and W., Spoiidylositm pulchrtim 

 var. planum, Wolle) and Dinobryon cylindricum dt. ; Sotryococeus 

 Braunii, Kutz., and Ccelosphxrium Kutzingianum, Jfag. ab. ; Tabel- 

 laria spp., Melosira granulata, Ealf s, and Spharocystis Schroetiri fr. 



Hawes Water 

 Bassenthwaite 



Diatoms dt. {Tabellaria spp.); Desmids ab. {St. jaculiferum) ; Coelo- 

 sphserium Kutzingianum, Siphmrocystis Schroeteri, Uudoriiia JBlegans, 

 Ehr., and Ceratium hirundinella, Miill. fr. 



Diatoms {Tabellaria and Asterionella spp.) and Dinobryon dt. ; P. Willei 

 and mixed Desmids ab. ; Eudorina elegans fr. 



Diatoms dt. {Tabellaria and Asterionella) ; Desmids and Ceratium 

 hirundinella fr. 





Diatoms {Tabellaria and Asterionella) and Ceratium hirundinella dt. ; 

 P. Willei ab. ; Desmids fr. 



Diatoms dt. {Asterionella) ; 'DesmidiS {StauraHrtim paradoxtim Meyen) , 

 Tabellaria and Ceratium hirundinella, ab. ; P. Willei, Melosira 

 granulata, Sphserocystis, JSudorina and Oscillatoria Aghardii, 

 Gromont, ir. 



ipiatoms dt. {Asterionella) ; Tabellaria, Dinobryon and Chroococctis spp. 

 ab. ; Sphserocystis, Desmids and Ceratium hirundinella fr. 



Windermere 







Esthwaite 



Diatoms {Asterionellci) and Myxopbycese {Oscillatoria, Anaboena spp.) 

 dt. ; Tabellaria ab. ; Ceratinm, P. Willei, Desmids and JSudorinn fr. 





* Frequency symbols : dt. -- dominant, ab. = abundant,//-. = frequent. 



* "The Phytoplankton of the English Lake District," 'Naturalist' (London), 1909, 

 p. 115. 



t " Periodicity of Phytoplankton of some British Lakes," ' Journ. Linn. See' (Bot.), 

 vol. 40 (1912). 



