138 



Part III. — Seventeenth Annual Report 



Table containing the Names of Entomostraca Captured in Tuw 

 Nets, with Date and Place of Capture. 



Abbreviations used :— ab.. abundant ; c, common ; fr., frequent ; f., few ; r., rare ; 0, none. 



Names of the Species. 



1897. 



1898. 



Lower end. 

 August 19. 



Upper end. 

 August 19. 



Lower end. 

 Nov. 24. 



i 



^ - 



Lower end. 

 March 22. 



Upper end. 

 March 15. 



Lower end. 

 June 21. 



Upper end. 

 June 29. 



Oopepoda — 





i 















Diaptomus gracilis . 





f. 



*f. 



*' 



* r 



f. 



*r. 



*fr. 



G. 6. Sars. 



















Cyclops strenuus, Fischer . 



fr. 



f. 



f. 



fr. 



r. 



f. . 



r. 



fr. - 



Cyclops leuckarti, Claus 



r. 



0 



0 



o 



0 



0 



0 



0 



Cyclops viridis (Jurine) . 



0 



0 



0 



o 



0 



r. 



0 



i 1 



Cyclops albidiis (Jurine) . 



0 



0 



0 



o 



r « 



0 



r. 



0 



Cladocera — 



















Sida crystallina (Muller) . 



0 



0 



0 



0 



0* 



0 



fr> 



0 



Simocephalus vetulus 



0 



0 



r. 



0 



0 



0 



0 



0 



(Miiller). 



















[DapAnia lacustris . 



c. 



f. 



ab. 



c. 



fr. 



fr. i 



fr. 



fr. 



G. 0. Sars. 



















Bosmiiia lonc/vrostris . 



0 



0 



0 



0 



0 



0 



f - 



0 



(Miiller). 



















Bosfliina longispina . 





f. 



f. 



0 



r - 



0 



fr. 



fr. 



Leydig. 



















Kuryi'fircus lamellatits 



0 



0 



0 



0 



0 



0 



fr' 



0 



(Miiller). 



















Polyphemus pedicuhts 



r. 



f. 



0 



0 



0 



0 



fr. 



fr. 



(Linn.). 



















Bytkotrephes longimamis . 



fr. * 



f. 



r. » 



0 



0 



0 



0 



f. 



Leydig. 



















Leptodora hyalina' . . 



c. 



f. 



0 



0 



o 



0 



r. 



f. 



Lilljeborg. 











J 



j 







It will be observed, in glancing at the distribution of the various 

 organisms, that only three of the species occurred in all the gatherings. 

 Polyphemus and Leptodora, though apparently distributed more or less all 

 over the loch at the date when the August and June gatherings were col- 

 lected, seem to have disappeared in November and March, as no specimens 

 were observed in the gatherings then collected. Bytkotrephes was frequent 

 in the gathering collected on the 19th August, but became rarer as the year 

 advanced. No specimens were collected in March, while in June a few 

 only were obtained at the upper end of the loch. It will also be observed 

 that Cyclops viridis and C. albidus among the Copepoda, and Sida, Simo- 

 cephalus, and Eurycercus among the Cladocera, occurred in only one or 

 two of the gatherings. The term " pelagic " can scarcely be applied to 

 these forms in the sense in which it is applied to Diaptomus gracilis, 

 Cyclops strenuus, or Daphnia. The species referred to were almost all 

 collected in comparatively shallow water ; and their presence in the 

 gatherings in which they occur may be due to the net having passed near 

 to some aquatic vegetation. In comparing the seasonal distribution of 

 the various species mentioned in the Table, Daphnia lacuslris appears 



* Diaptomus gracilis was more frequent in the fine silk tow-net gatherings than in the 

 gatherings collected with the other net. 



. f No male Daphnia was observed in any of the gatherings ; but the females were 

 found, frequently with pseudova, in almost every gathering. 



