of the Fishery Board for Scotland. 



153 



Y._ON THE DISTRIBUTION OF PELAGIC INVERTEBRATE 

 FAUNA OF THE FIRTH OF FORTH AND ITS VICINITY 

 during the Seven Years from 1889 to 1895, both inclusive. By 

 Thomas Scott, F.L.S., Mem. Soc. Zool. de France. (Plates IV., 



v., VI., vri.) 



CONTENTS. 



PAGE. 



Introductory, 1 53 



Invertebrates Captured by the Tow -nets, 155 



(1.) The Mollusca, 155 



(2.) The Crustacea — [a) Decapoda, 156 



(6) ScMzopoda, 158 



(i.) The Euphausiidce, 160 



(n.) The Mysidce, 160 



(c) Cumacea, 167 



{d) Isopoda, 168 



(e) Amphipoda, 170 



{/) Cladocera, 177 



{g) Copepoda, . . . . . . . .177 



(3.) The Vermes— /S'a^7^■«a, etc., 190 



(4.) The Coelenterata — Ctenophora and Hydromedusce, .... 194 



(5.) Larval and Young Crustacea, ........ 197 



(6.) Pelagic Fish Ova, 203 



(7.) Explanation of the Charts, 207 



(8.) List of named species of Mollusca, Crustacea, etc., .... 209 



INTRODUCTORY. 



The scientific investigations that have until recently been carried on in 

 the Firth of Forth, and also outside the limits of the estuary, included 

 among other things the examination of the various groups of pelagic in- 

 vertebrates that form so important a part of the food of fishes. The 

 examination was carried on chiefly in connection with the trawling opera- 

 tions of the Garland, the steam cruiser set apart specially for scientific 

 work. The trawling experiments of the Garland were made over certain 

 fixed portions of the estuary and neighbourhood which were denominated 

 ^' stations." The method adopted for the examination of the pelagic in- 

 vertebrates was somewhat as follows : — During the time that each station 

 was being trawled two tow-nets were kept constantly at work. One of 

 these was towed at about half a fathom below the surface of the water, 

 and was distinguished as the surface tow-net ; the other was fastened to 

 the end of the beam of the trawl in such a way as just to clear the 

 bottom, and was distinguished as the bottom tow-net. Sometimes other 

 nets were used at intermediate depths, but not with the same regularity 

 as the first two. The gatherings collected with these mid-water nets are 

 therefore not specially referred to in this paper. The tow-nets at first in 

 use were comparatively of small size, but subsequently a larger kind, 

 somewhat similar to those that had been used on board the Challenger, 

 were adopted, and are still used in connection with the Board's scientific 

 work. 



At first nine experimental stations were selected for the carrying out of 

 special scientific work, but this number was afterwards increased to ten. It 

 has not, however, been considered necessary for the purposes of this paper 

 to take note of the published statistics for all these stations, and therefore 



