134 



Part III — Seventeenth Annual Report 



staff or pole) worked about amongst the vegetation along the shore. 

 Interesting results were sometimes obtained in this way, and generally, 

 though individuals were much fewer than in the tow-net gatherings, the 

 variety of organisms was greater. The gatherings collected with the tow 

 nets and hand nets were transferred to separate bottles and preserved in 

 methylated spirit for subsequent examination. 



In the preliminary remarks in last year's paper on the fresh-water lochs 

 already referred to, it was also stated that, besides the examination of the 

 eight lochs previously mentioned, a somewhat similar series of observations 

 was being made in the three lochs in the line of the Caledonian Canal — 

 viz., in Loch Ness, Loch Oich, and Loch Lochy. These lochs have been 

 tow-netted at various times by the s.s. " Garland " when passing to and 

 from the West Coast. This work was attended to principally by Mr. F. 

 G. Pearcey, naturalist on board the vessel. Various circumstances con- 

 nected with the work of the "Garland" prevented these lochs from being 

 examined with the same regularity as the others. The results of the two 

 series of observations are described separately. 



The thermometers used in all these investigations were the Negretti and 

 Zambia deep-sea reversing thermometers, as used on board the " Garland." 



In describing the results of the examination of these lochs, each loch, 

 will be considered apart from the others. After referring to any point of 

 interest concerning the loch itself, the temperature of the water and the 

 other physical observations connected therewith that were recorded each 

 time the loch was visited will be first referred to ; a list of the free- 

 swimming entomostraca that have been captured in the tow-nets will be 

 given next ; and afterwards a list of the species of Crustacea and mollusca 

 obtained in the shore gatherings. Questions relating to seasonal variation, 

 distribution of species, etc., will also be discussed ; while notes on a 

 number of the rarer and more interesting species obtained are added at 

 the end. 



The Entomostraca, being the most important group of the higher fresh- 

 water invertebrates, will, along with other crustacean species, be noticed 

 in the present paper ; any mollusca observed will also be included ; but 

 the lower forms, the infusoria and micro-algae, will be treated 

 separately later on. 



The following Table gives the names of the various lochs referred to in 

 the present paper and the dates on which they were examined : — 



First Series. 



Names of the Lochs. 



Dates of Examination. 



. 1897. 



1898. 



Loch Achray, 



Sept. 



10 



Nov. 



27 



Mar. 17 



June 



28 





Loch Arklet 





!t 





26 



„ 15 





27 









16 



Dec. 



10 



h 31 



July 







Duddingston Loch, 





1* 





15 



,, 2 



June 



15 



Sept. 16 



Forfar Loch, . . . . 



July 



24- 



Nov. 



3 



» 1 





16 





Loch Leven, .... 



Sept. 





Dec. 



1G 







13 





Loch Lomond— Upper end, . 



Aug. 



20 



Nov. 



25 



„ 15 





29 





,, Lower end, . 









24 



22 





21 





Loch Katrine — Upper end, . 



Sept, 



9 





26 



,, 16 





27 





,, Lower end, . 





10 





26 



„ 16 





28 





* Duddingston Loch and Forfar Loch were not tow-netted at these dates. 



