1904 - 5 .] The Plankton of Thingvallavatn and Myvatn. 1161 
more substantially than I have been able to do. It is necessary 
to bear in mind that all the samples which the authors have used 
for their investigations only have been collected in July-September 
(Messrs West, p. 477). Without regular fortnightly or monthly 
explorations of the lakes, it is quite impossible to obtain 
a well-founded idea with regard to most of these points, and such 
regular explorations in the Scottish lakes are as yet only a 
desideratum ; at all events, nothing has been published upon this 
point. In particular, it must be noted that the great maxima of 
Diatoms are always to be found in spring and in autumn, and that 
the maxima of Oscillatoria and Lyngbya, especially the latter, in 
our lakes are often extremely short and therefore only traceable 
by means of very thorough explorations. 
C. W.-L. 
List op Literature. 
1892. Bergendal (D.), “Beitrage zur Rotatorienfauna Gron- 
lands,” Lunds Universitets Aarsskrift, xxviii. p. 1. 
1897. Borge (0.), Botaniska Notiser, p. 211 : “ Algologiska 
Notiser. Siisswasserplankton aus der Insel Mull.” 
1900. Borge (0.), “Schwedisches Siisswasserplankton,” ibid., p. 1. 
1902. Brehm (Y.), “ Zusammensetzung, Verteilung und Perio- 
dicitat des Zooplankton im Achensee,” Zeit. d. Ferdinandeums, 
iii. F., Innsbruck, xlvi. p. 1. 
1898. Borgesen (F.), “Nogle Ferskvandsalger fra Island,” 
Botanisk Tidsskrift , xxii. p. 131. 
1902. Borgesen (F.) and Ostenfeld (C. H.), “Phytoplankton 
of Lakes in the Faeroes,” Botany of Faeroes , Kobenhavn, ii. 
p. 613. 
1902. Chodat (R.), Algues vertes de la Suisse, Bern. 
1899. Cleve (A.), “Notes on the Plankton of some Lakes in 
Lule Lappmark, Sweden,” Oevers. af Kgl. Svenska Vetensk. Akad. 
Forhandl., No. 8, p. 825. 
1889. De Guerne (J.) and Richard (J.), “ Sur la faune des 
eaux douces du Greenland,” Comp. Rend., cviii. p. 630. 
