of the Fishery Hoa rd for Scotland. 



179 



The highest surface temperature is 65'0 degrees, and the lowest 43*1 

 degrees — showing a diiierence of 2 1"9 degrees; whereas the difference 

 between the highest and lowest surface temperature readings for Loch 

 Ness is 14*9 degrees, or only about two-thirds of the difference 

 observed in Loch Oich. There is a marked difference in the temperature 

 of the water on 6th August 1897 and 4th August 1898. On the latter 

 date the temperature of the water is practically uniform — down, at least, to 

 ten fathoms ; while on 6th August 1897 there is a difference between the 

 temperature at the surface and at 15 fathoms of 16 degrees Fahrenheit. 



m 



The Pelagic Entomostraca Collected by the Totr-Nets. 



The names of the various species observed in the tow-net gatherings 

 from Loch Oich will be found in the annexed Table : — ■ 





Dates. 



Names of the Species. 



1897. 



1898. 





Aug. 6. 



Dee. 7. 



Jan. 24. 



Aug. 4. 



Oct. 6. 



COPEPODA. 













Diaptomus gracilis, (i. 0. Sars, - 



r. 



f. 



f. 



c. 



fr. 



,, liar im, Brady, - 



0 



0 



0 



r. 



0 



Cyclops strenuus, Fischer, - 



r. 



0 



0 



f. 



fr. 



viridis (Jurine), 





r. 



r. 



0 



0 



albidus (Jurine), - 



0 



0 



0 





0 



Clacoceha. 













Sida crystallina (Muller), - 



f. 



0 



0 



f. 



r. 



Diaphanosoma brachyurum (Lievin), - 



0 



0 



0 



f. 



0 



Daphnia galeata, G. 0. Sars, 



a!». 



f. 



f. 



fr. 



ab.* 



Bosmina longispma, Leydig, 





f. 



f. 



e. 



r. 



Holopedium gibberum, Zaddach, 



r. 



0 



0 



r. 



'• 



Camptocercus rectirostris, Schcedler. - 



0 



0 



0 





r ' 



A lona affinis, Ley dig, - - - 



0 



0 



0 





o 



Polyphemus pedicul w (Linn.), - 



r. 



0 



0 





r. 



Bythotrephu longimanus, Leydig, 



fr. 



0 



0 



fr. 



f. 



Leptodora hyalina, Lilljeborg, - 





0 



0 



fr. 



fr. 



* Male Daphnia were frequent in the gatherings collected at this date. 



Among the Copepoda observed in Loch Oich, Diaptomus gracilis was 

 the most common. It was also one of the few species that occurred in 

 all the gatherings examined. 



Diaptomus hircus, Brady, appeared to be rare in Loch Oich. The 

 three species of Cyclops were also apparently scarce. 



Sida and Diaphanosoma were also somewhat rare, but Sida was less 

 so than the other. In the gatherings collected in August 1897 Sida 



