RECENT HYDROBIOLOGICAL INVESTIGATIONS 477 



Scotland, probably because of the outflow of relatively fresh 

 water from the Clyde and Irish Sea, and also because of the 

 shoaling of the sea. We have seen that comparatively little 



Fig. i. — The isohalines in the British and Norwegian Seas. 



The values represent the salinity (grams of total salts per 1,000 grams of water). The thin broken lines 

 indicate the approximate positions of the main hydrographic sections. (From Rapports et Proces- 

 Verbaux, International Council for the Exploration of the Sea, vol. x. 1909.) 



Atlantic water enters St. George's Channel from the south, and 

 this is still more so with regard to the northern entrance into 

 the Irish Sea. The channel between Scotland and Ireland is 



