CRUSTACEA OF XORTHUMBEELAND AND DURHAM 



Crustacea of Northumbeiiand and Durham compared with 

 those of some other parts of the country and seas : — 



The character of the fauna of the coasts of Northumberland 

 and Durham is distinctly boreal, and much more northern 

 than that of the same latitude on our western shores. As 

 long ago as 1868 one of us wrote, "The distribution of animal 

 life around our coasts appears for the most parts to have 

 followed the direction south, west, north, and east. It would 

 seem that comparatively few (if any) southern species have 

 made their way far north through the Straits of Dover, 

 which may probably be accounted for by the fact that that 

 channel has, geologically speaking, been only a short time 

 open. As a rule southern species are to be seen at a higher 

 latitude on the western than they are on the eastern coasts. 

 There are, however, some apparent, but only apparent ex- 

 ceptions. These consist of animals known on the north-east 

 coast of Scotland, which we should not have expected to meet 

 with there. On examining into the probable cause of tiicir 

 migration to this district, I am led to believe that thuy have 



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