NOTES ON CORNISH CRUSTACEA. 



303 



stony gravel in 20 fathoms almost due south of Prussia Cove in 

 Mount's Bay. A single specimen has been procured on the 

 north coast at Zennor. At Scilly it has been captured to the 

 north of Menavawr in 40 fathoms. G. dispersa, Spence Bate, is 

 at least fairly common everywhere from 10 fathoms downwards, 

 while on many trawling grounds it is plentiful, and at times 

 abundant. Females in berry occur in March and from the 

 middle of July till the middle of August. 



The Crawfish, Palinurus vulgaris, Latr., is taken in large 

 quantity annually all round the coast and at Scilly, and ranks in 

 importance with the Lobster and the Edible Crab. Though 

 often found inshore it is most plentiful, of largest size, and of 

 finest condition in deep waters, where its most congenial haunts 

 are on rocky and on " scuddy " ground, in sandy lanes among 

 rocks, and indeed wherever sand and rock come together. 

 Females in berry are found for the most part in April and May. 

 Though Dr. Borlase referred to a Mount's Bay specimen of the 

 " shrimp," now known as Arctus ursas, Dana, as far back as 

 1758, it is one of the rarest of Cornish Crustacea. One specimen 

 has been obtained five miles south of the Eddystone (M. B. A.), 

 one was taken off Polperro by Laughlin, several have been cap- 

 tured about Penzance at different times by T. Cornish and others, 

 one has been found off Land's End, and one near the mouth 

 of the Bristol Channel (Cornish). 



The Lobster, Astacus gammarus (L.), the Homarus vulgaris of 

 Milne-Edwards and many subsequent writers, is generally dis- 

 tributed and often abundant, from shallow water down to 

 50 fathoms, for the most part among rocks, but sometimes on 

 sand and gravel. It occurs all round the coast, but reaches its 

 maximum development as regards size and probably also as 

 regards population in the deep waters to the south-west and west, 

 and especially from the Land's End district outwards to some 

 miles west of Scilly. The quantity captured naturally fluctuates 

 from season to season, but on the north coast it is much less 

 abundant now than twenty years ago. 



Nephrops norivegicus (L.), the Norwegian Lobster, is frequently 

 brought in by trawlers, especially from forty miles west of the 

 Longships (Norman), and from a few miles W.S.W. of the Bishop. 

 It is occasionally obtained by the French crabbers between 



