THE ZOOLOGIST 



No. 818— August 1909. 



NOTES ON CORNISH CRUSTACEA. 

 By James Clark, M.A., D.Sc, A.R.C.S. 



I. Brachyura and Macrura. 



Probably nowhere in Great Britain are conditions so favour- 

 able for variety and abundance of Crustacean life as in Cornwall. 

 Its unique geographical position as the most westerly and most 

 southerly county in England, and the consequent genial tem- 

 perature of its waters ; its form as a great wedge projecting out 

 into the Atlantic ; its two hundred and fifty miles of much 

 indented and irregular coastline; its variety of littoral and 

 diversity of sea-bottom; its rocky islets and western archipelago; 

 its land-locked caves and tidal estuaries ; its large sheets of 

 sheltered sea and long stretches of coastal waters exposed to the 

 full force of Atlantic storms — all these contribute to a variety of 

 environment sufficient to attract every type and section of the 

 marine Crustacea of Western Europe except the exclusively 

 boreal. In addition to these, its currents and prevailing winds 

 and the manifold sources of its surface waters and plankton 

 provide unusual facilities for the advent of waifs and strays, 

 while its varied shipping is occasionally responsible for the intro- 

 duction of casual wanderers of assisted passage. 



The resulting wealth of Crustacean life has naturally attracted 

 a fair amount of attention both from resident and from visiting 

 naturalists. Jonathan Couch, of Polperro, his son Richard 



Zool. 4th ser. vol. XIII., August, 1909. z 



