CRUSTACEA. 



71 



Edwards says that it is very common in the Mediterranean. 

 Risso does not mention it, unless, as is not improbable, that his 

 species of P. Leachii be identical with it. 



Portunus pusillus. — Dwarf Crab. — Leach., Malae. Brit. Crust., 

 t. ix ; Milne Edwards, Hist. des. Grust., t 1, p. 444 ; Bell, Brit. 

 Stalk-Eyed Crust., p. 112. 



P. Maculatus. — Risso, Hist. Nat. En Merid., V, p. 5. 



Common. Bell says that this species inhabits deep water 

 and is common on the Coasts of Devonshire and Cornwall. It is 

 found from the Isle of Man to the Mediterranean sea, from which 

 it has been recorded by Risso and Roux. 



Its ordinary size is about four lines in length. But Mr. 

 McAndrew took a male off the Isle of Man fully an inch in 

 breadth and eight tenths of an inch in length. 



PINNOTHE£IDJE.—(Pakasitic Crabs.) 



Genus, Pinnotheres. — Fair, Leach, Edwards. 



Antennse small, short, eyes impoverished, small, on short pe- 

 duncles ; carapace round, globular; chelae, sub-equal, legs short. 

 These crabs inhabit the shells of bivalve Mollusca. 



Pinnotheres pisum — Pea Crab. — Pennant, pi. 1, fig. 1 ; Leach, 

 Malac. Brit., t. 14 : Milne Edwards, Hist, des Crust., t. 1,p. 30; 

 Bell, Brit. Stalk Eyed Crust., p. 121. 



"This species seems rare with us and only found in the Mussel 

 shell, the natural inhabitant of which it either finds diseased or 

 renders so. I have never found it in the Pinna as reported by 

 authors, though many have been examined for that purpose." 



Mr. Ball informed Mr. Bell that he had, on two occasions, 

 taken a great number of Pinnotheres, which were all males, from 

 Cardium edulis (the common cockle), nine out of every ten con- 

 tained a crab. On opening oysters at Tenby, in Wales, he has 

 likewise procured this crab, and says that at every age it gener- 

 ally selects such shell as with out-stretched legs it would fill 

 from side to side. 



The young or zcea of this crab has been described and figured 

 by Mr. Vaughan Thompson in the Entomological Magazine, 

 vol. iii, p. 88, which has been copied into BelVs British Stalk-Eyed 

 Crustacea, as a vignette to page 125. 



