168 



Mr. W. West and Dr. G. S. West. [Oct. 30, 



II. Scottish Lakes. 



Extensive collections of phytoplankton were made in various parts of 

 Scotland, but especially in the west and north-west, in August, 1901, May 

 and August, 1902, April, July, August, and September, 1903, nnd August, 

 1907. The areas comprised Perth, Inverness, Eoss, Sutherland, and the 

 Outer Hebrides. We have also examined a number of collections made by 

 Mr. James Murray of the Scottish Lake Survey (Pullar Trust). In all, we 

 have examined phytoplankton from 38 of the most important of the Scottish 

 lochs. The results of these investigations have already been published,* 

 the previous work being represented by a short report by Borge on some 

 phytoplankton from the Island of Mull.f Mr. James Murray has also 

 examined the plankton of a very large number of the Scottish lochs, and has 

 at different times commented upon the occurrence and distribution of the 

 phytoplankton.^ Further remarks upon the Scottish phytoplankton have 

 been made by Wesenberg-Lund in comparing it with the plankton of the 

 Danish lakes,§ and still more recently a paper has appeared by Bachmann|| 

 comparing the results of Scottish material with plankton from the* Swiss 

 lakes. 



The Scottish phytoplankton is largely Chlorophyceous, and is conspicuous 

 for the large number and great variety of its Desmids, among which the 

 following are perhaps the most noteworthy: Xanthidiuvi sulhastiferum, 

 Stcmrastrum anatinum, St. Ophiura, and St. jacidiferum. In some of the 

 lochs, Mesotceniimi macrococcum occurred as a normal constituent of the 

 plankton. This is a most interesting adaptation of a colonial wet-rock 

 species to a limnetic life, with an accompanying reduction in size of the 

 colonies and their assumption of a spherical form. A similar adaptation of 

 the mucous colonies of Cosmocladium saxonimm to a limnetic existence is 

 also found in both the Scottish and the Irish lakes, but much less frecpuently. 



In the smaller and more elevated lochs, Microspora amcena is a characteristic 



* W. and G. S. West, in 'Linn. Soc. Journ. Bot.,' vol. 35, Nov., 1903 ; in 'Koy. Soc. 

 Edin. Trans.,' vol. 41, part 3, 1905. 



t Borge, ' Algol. Notis. 4, Siissw.-Plankton aus Insel Mull,' Botaniska Notiser, 1897. 



I Vide James Murray, in ' Boy. Physical Soc. Edin. Proc.,' vol. 16, June, 1905 ; and in 

 various reports, under the direction of Sir J ohn Murray, on the Bathymetrical Survey of 

 the Freshwater Lochs of Scotland in the 'Geograph. Journ.,' 1900 — 1908. 



§ Wesenberg-Lund, in 'Roy. Soc. Edin. Proc.,' vol. 25, part 6, 1905 ; also in appendix 

 to a subsequent paper,, ibid., part 12, 1906. 



|| Bachmann, in ' Archiv fur Hydrobiol. u. Plank tonkunde,' vol. 3, 1907. It should be 

 mentioned, however, that some of Bachmann's records are open to serious doubt. His 

 identifications do not appear to be strictly accurate. We might ask, among many other 

 questions, " What is Cosmariurn lunaria ? " He also copies Tanner-Fulleman's records, 

 some of which appear to be equally doubtful. 



