182 ARCIDJE. 



sen has dredged it on the coast of Norway in 10-20 

 fathoms, and Malm on the coast of Sweden in 80-100 

 fathoms. M 'Andrew has taken it alive on the Spanish 

 shore ; and Forbes has recorded its range of depth in 

 the iEgean as 30-80 fathoms. 



The valves of this curious shell are so deep, that 

 Lister mistook them for sessile Barnacles, and called 

 them Balanus Bellonii. The animal is very shy and 

 sensitive. According to Mr. Clark a glutinous fluid 

 appears to exude from a special gland to supply the 

 byssus, which is moulded by the foot. Capt. Brown 

 says the shell " burrows in hard clay and limestone 

 rocks " ; but this does not accord with my observation 

 of its habits. 



In all probability this is the Norwegian shell men- 

 tioned by Linne, in his ' Sy sterna Naturae/ as like A. 

 tortuosa but of much smaller size. That species in- 

 habits the Indian Ocean. Miiller applied the above 

 name, in his 'Prodromus/ to what appears to be the 

 present species, and Pennant did the same in his ' British 

 Zoology/ Lamarck called it A. cardissa. Montagu 

 and subsequent writers on British conchology considered 

 it was the A.ficsca of Solander's MS., although Bru- 

 guiere's species of that name is different. Turton, in 

 his ' Conchological Dictionary/ mistook it for A. Noa 

 of Linne, a well-known Mediterranean shell, which has 

 never been authenticated as a native of the British seas. 

 Philippi and Loven adopted Bruguiere's name, navi- 

 cularis ; but that species is stated to inhabit the coast 

 of St. Domingo, and is very unlike our shell. Mr. Reeve 

 has added another name (Britannica) to this long list. 

 Weinkauff has, on the other hand, proposed a reduc- 

 tion of the catalogue, by uniting the present species 

 with A. No<2. He says that he has found specimens at 



