Mactra glauca von Born, 1778

English Channel to Morocco, Mediterranean. Intertidal to 50m deep, in sand. Synonyms: helvacea Lamarck, neapolitana Poli. Málaga, Andalucia, S. Spain. 102mm.

In beach drift among gravel, Cap d’Agde, Occitania, S. France. 54mm.

Málaga Bay. Trawled at 30-80m deep. 111,5mm. Original picture provided by J.M. Martin (ES). – (CC BY-NC-SA) –

A large specimen trawled in Saint-Brieuc bay, Côtes d’Armor, N. Brittany, NW. France. 115mm.

Mactra glauca in T. Brown, Illustrations of the recent conchology of Great Britain and Ireland plate XLI, London 1844, via BHL.   « Shell subtriangular, thin ; anterior side slightly wrinkled ; umbones somewhat obtuse, a little reflected, with a narrow intervening gap ; surface of a cream-yellow colour, very finely striated transversely, and with irregular, broad and narrow glaucous radiations of a pale brown-colour ; inside of a pale cream-colour, or purple ; margins thin, and sharp. Found on the coast of Cornwall ; but I am not aware that any living specimens have been met with, the locality not having been yet detected. »

Internal view of the left valve of a specimen collected at extreme low tide on sand bank, Les Noires, Saint-Malo, N. Brittany. 87mm. Notice the sharp turn of the pallial sinus, under the posterior muscle scar at left.

The species in E. Donovan: The natural history of British shells, vol. IV, London 1802, plate CXXI.   « Though hitherto unknown as a British shell, it has been before discovered in the Mediterranean sea; for there can be no hesitation in admitting it to be the shell figured by Chemnitz, as above quoted. Gmelin refers to the two figures in that Work, No.232, and 233, for this species glauca; and the description corresponds in general with them, though not exactly in the colour of the rays. »

The hinge, typical of the genus, in the specimen from Málaga.

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