FAUNA OF THE CLYDE SEA-AEEA. 



445 



Before proceeding to enumerate the s])ecies obtained, it seems 

 advisable to say a few words regarding the mode of procedure 

 adopted in collecting, for tliis probably explains certain general 

 features in the results obtained. In the great majority of in- 

 stances the instrument employed was a shrimp-trawl, which was 

 found on the whole more convenient for working in these loca- 

 lities than the dredge, owing to its bringing up a less amount of 

 mud and a greater variety of forms. Certain groups, such as 

 the MoUusca, are not obtained in such large numbers as by the 

 dredge, and hence the list of these animals obtained is small as 

 compared with that known to inhabit the district. 



A tow-net was generally attaclied a short distance above the 

 trawl, so as to capture any Crustaceans which might be swimming 

 just above the bottom. These were almost invariably found to 

 be of a dilferent species from those taken in the net-s which were 

 dragged at the surface. 



Statement of Hksults. 



For convenience I have drawn up the results in the form of a 

 Table, with a column corresponding to each basin. The figures 

 show the range in fathoms in that particular region, whilst there 

 is appended in another column a sketch of the distribution of 

 each form outside the British area. Those lacts which have been 

 taken from the published writings of others are indicated by 

 italics. A note of interrogation indicates that I have obtained 

 the species in that locality, but the record of tlie exact depth 

 has been lo-;t. d means that dead shells, not living specimens, 

 were obtained. 



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