Shell small to medium-sized, in which the two valves are no more an articulated protective system but have turned into a set of scraping tools gaping anteriorly. The two valves are linked to the body of the animal by spoon-shaped apophyses placed anteriorly, near the umbones. In the adult, supplementary plates appear, in order to provide some flexible protection.
 

« Shell bivalve, with elongated valves, rounded and entire at both ends, gradually acuminate towards its posterior part; an oval accessory piece, slightly convex. » – A. Risso: Histoire naturelle des principales productions de l’Europe méridionale vol.IV, Paris 1826, p.376. Valves not gaping at their extremities.
 

Synonym Cadmusia Leach, who writes: « The shells short, equivalve : that part of the epidermis covering the respiratory tubes is testaceous ; the accessory valves two, unequal, post-umbonic, delineating an angle. The tracheal tubes short. The foot short and obtuse. » – W. E. Leach: Molluscorum Britanniae Synopsis, London 1852, p.254.
 

« The name of Pholas is very old, since it already appears in Athenaeus. It was also used by the authors of the Renaissance and definitively fixed by Lister (1687), from which Linnaeus borrowed it. » – Bucquoy, Dautzenberg & Dollfus: Les mollusques marins du Roussillon vol.II fasc.24, Paris 1896, p.609. Linnaeus: « Shell bivalve, divaricate, often with smaller accessory plates. Hinge recurved, ligament cartilaginous » (Syst. Nat. vol.I p.669). Valves gaping at each end.