166 Part III. — Seventeenth Annual Report 



Temperature and other Physical Observations, 



The following Table shows the temperature readings recorded on the 

 four occasions when the loch was tow-netted : — 







Temperature. 



Wind. 







Date. 



Hour. 



Air. 



Water. 



Direction. 



Force. 



Weather. 



Surface Movement 

 of Water. 







Surf. 



5£ Ft. 



— Ft. 







1897. 

 Dec. 15 



1898. 

 Mar. 2 



June 15 



11 a.m. 

 Noon. 



Degs. 

 48-2 

 45-0 

 62-1 



Degs. 

 35-7 

 360 

 62-0 



Degs. 

 36-0 

 30-0 

 62-0 



Degs. 



Southerly. 

 S. Westerly. 

 Easterly. 



Light, 



S'm'wh't 

 squally. 

 Light. 



Dull; show- 

 ery. 

 Sky clear. 



Slight haze. 



Slight ripple. 

 Moderate. 

 Slight ripple. 



Sept. 16 





78-0 



61-0 



CO -4 





Westerly. 



Light, 



Sky clear. 



Slight ripple. 



The difference between the highest and lowest surface temperature is 

 26*3 degrees Fahrenheit. The surface and bottom temperatures were also 

 nearly uniform on each of the four visits, and the readings for December 

 and March were practically the same, while those for June and September 

 differ at most only 1*6 degree. It will also be observed that it is the 

 September readings that are the lowest of these two, and that notwith- 

 standing the much higher temperature of the air. 



Pelagic Entomostraca Captured by the Tow- Nets. 



As might have been expected, the tow-net gatherings collected in 

 Duddingston Loch yielded a somewhat greater number of Entomostracan 

 species than was observed in some of the other lochs examined. This 

 loch being shallow, plants growing on the bottom are able to send their 

 leaves and stems well up towards and even above the surface of the 

 water, and afford shelter and foothold to many species that do not usually 

 adopt a free-swimming life — like Daphnia and one or two other forms. 

 In towing the nets through the water it was scarcely possible to avoid at 

 times coming in contact with those plants and capturing some of the 

 organisms that might be clinging to them : hence the greater variety of 

 forms observed in these gatherings. The following Table contains the 

 names of the various species of Crustacea observed in the tow-net 

 gatherings collected in Duddingston Loch. 



[Table. 



