258 CRUSTACEA OF NORTHUMBERLAND AND DURHAM 



and England; on many occasions as far as north York- 

 shire. The species thus occurring are not known (or very 

 rarely?) at other times of the year, and the conclusion the 

 writer arrived at was that at the period of the year mentioned 

 there was a strong southerly current sweeping along our east 

 coast. The Arctic forms which peculiarly distinguish this 

 southerly migration are Clione limacina Phipps, Thysanoessa 

 longicandata Kroyer, Nematoscelis borealis Norman, and 

 Euthemisto compressa Goes. 



These conclusions, arrived at on purely zoological grounds, 

 have received remarkable confirmation during the last two or 

 three years from the physical researches of the International 

 Council for the Exploration of the Sea. By numerous and 

 extended observations and experiments it has been clearly 

 established that water which enters the North Sea through 

 the Straits of Dover is very soon deflected from its northerly 

 course, and flows eastwards to the continental portion of the 

 area ; and that on the other hand strong currents come from 

 the north, along the western side of the channel; and not 

 only so, but that the exact course of these southern-flowing 

 waters, and also the amount of their saUnity, varies at different 

 seasons of the year. 



The following Crustacea of the orders Brachyura, Anomura, 

 and Macrura, so well known in the south of our islands, are 

 wholly absent from the north-east coast of England : — 

 ^'' Ebalia tumefacta Montagu. 

 Thia polita Leach. 

 Poly bins Henslowi Leach. 



* Portunus arcnattis Leach. 

 Bathynectes longipes Risso. 

 Xantho floridus Montagu. 



* hydrophilus Herbst. 

 Concha Bell. 



Pilumnus hiftellus Pennant. 

 JVautilograpsns mimitns Linne. 



* The species in this list to which an * is prefixed have been recorded from the 

 coast of Norwaj, 



