BRITISH STALK-EYED CRUSTACEA. 179 



The colour of this species varies, particularly in the case of 

 the male, which is usually of a pale yellowish brown, somewhat 

 mottled ; the female is yellow, with brownish markings, the brown 

 sometimes having a reddish tinge. Pinnotheres pisum is found in 

 the shells of several species of Mollusca. We have found it 

 chiefly in that of the common mussel, Mytilus edulis, from 

 Southend. This species is very generally distributed. It has 

 been recorded from St. Andrew's, in Modiolus modiole ; from 

 Devon, in Mytilus, Cardium, and Ostrea ; and Couch, in the 

 ' Cornish Fauna,' says it is rare, and only found in the shell of the 

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

 leaves it so. In Norfolk they are considered poisonous, and are 

 known as " Swinards." 



Pinnotheres veterum, Bosc. 



This species, which is much rarer than P. pisum, is known as 

 the Pinna Crab, and also as the Ancient Pea Crab. It is larger 

 than the former specie's, being often of a length of five-eighths of 

 an inch. In general habits it much resembles P. pisum, with the 

 exception that it is found chiefly in the shells of the Pinna ; in 

 colour, too, it varies, this species being of an uniform brown tint, 

 and devoid of the markings that characterise P. pisum ; it is 

 interesting to note that the tint of P. veterum corresponds in 

 colour to the mantle of its host, the Pinna. The following is a 

 short description of a specimen which we recently obtained from 

 about thirty miles off the Devon coast, in deep water, from a 

 Pinna: — Length of carapace, five-eighths of an inch. Colour of 

 an uniform dirty umber-brown, with a darker tinge down the 

 centre of the abdominal segments and the latero-anterior portion 

 of the carapace. Eyes of a rich pink. Sex female. Abdominal 

 segments extremely large and broad, covering the whole of the 

 sternum. 



It is recorded in the reports of the British Association 

 from Devon coast; and in the 'Cornish Fauna' as rare on that 

 coast. 



As the fables of the association of the Pinna and Pinnotheres 

 of Pliny and other early naturalists are so well known, we need 

 not do more than refer to them. That the crab finds the habitat 

 in the Pinna-shell of advantage there can be no doubt, but it 



