Any of more than 400 species (family Pectinidae) of marine bivalves found worldwide, from the intertidal zone to deep waters. The two halves of the shell (valves) are usually fan-shaped, except for a winglike projection at either side of the straight hinge. The shells are 1–6 in. (2.5–15 cm) long. They may be smooth or ribbed and red, purple, orange, yellow, or white. Cilia filter microscopic plants and animals from the water and move them toward the mouth. Scallops swim by clapping the valves, propelling themselves forward. The muscle that closes the valves is a popular food item.
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Like the true oysters (family Ostreidae), scallops have a central adductor muscle, and thus the inside of their shells has a characteristic central scar, marking the point of attachment for this muscle. The adductor muscle of scallops is larger and more developed than that of oysters, because they are active swimmers; scallops are in fact the only migratory bivalve. Their shell shape tends to be highly regular, recalling one archetypal form of a seashell, and because of this pleasing geometric shape, the scallop shell is a common decorative motif.
Most scallops are free-living, but some species can attach to a substrate by a structure called a byssus, or even be cemented to their substrate as adults (e.g. Hinnites spp.). A free-living scallop can swim, by rapidly opening and closing its shell. This method of locomotion is also a defense technique, protecting it from threatening predators. Some scallops can make an audible soft popping sound as they flap their shells underwater, leading one seafood vendor to dub them "singing scallops". The name scallop originated in the ancient Canaanite sea port Ascalon (modern city of Ashkelon, Israel).
In Western cuisine, scallops are commonly sautéed in butter, or else breaded and deep fried. Scallops are commonly paired with light semi-dry white wines. In the U.S., when a scallop is prepared, usually only the adductor muscle is used; the other parts of the scallop surrounding the muscle are ordinarily discarded. Sometimes markets sell scallops already prepared in the shell with only the adductor muscle intact. Outside the U.S. the scallop is often sold whole.
Scallops that are without any additives are called "dry packed" while scallops that are treated with sodium tripolyphosphate (STP) are called "wet packed". STP causes the scallops to absorb moisture prior to the freezing process, thereby getting a better price per unit of weight. The freezing process takes about two days.
In European cuisine, scallops are often prepared in the form of a quiche or cooked and then set into a savoury custard. In Japanese cuisine, scallops may be served in soup or prepared as sashimi or sushi. Dried scallop is known in Cantonese Chinese cuisine as conpoy (乾瑤柱, 乾貝, 干貝).
In a sushi bar, hotategai (帆立貝, 海扇) is the traditional scallop on rice, and while kaibashira (貝柱) may be called scallops, it is actually the adductor muscle of any kind of shellfish, e.g. mussels, oysters, or clams.
Scallops have lent their name to the culinary term scalloped, which originally referred to seafood creamed and served hot in the shell (Rombauer 1964). Today it means a creamed casserole dish such as scalloped potatoes, which contains no seafood at all.
The scallop shell is the traditional emblem of Saint James the Greater and is popular with pilgrims on the Way of St James to the apostle's shrine at Santiago de Compostela in Spain. Medieval Christians making the pilgrimage to his shrine often wore a scallop shell symbol on their hat or clothes. The pilgrim also carried a scallop shell with him and would present himself at churches, castles, abbeys etc. where he could expect to be given as much sustenance as he could pick up with one scoop. Probably he would be given oats, barley, and perhaps beer or wine. Thus even the poorest household could give charity without being overburdened. The association of Saint James with the scallop can most likely be traced to the legend that the apostle once rescued a knight covered in scallops. An alternate version of the legend holds that while St. James's remains were being transported to Spain from Jerusalem, the horse of a knight fell into the water, and emerged covered in the shells.
One legend of the Way of St. James holds that the route was seen as a sort of fertility pilgrimage, undertaken when a young couple desired to bear offspring. The scallop shell is believed to have originally been carried therefore by pagans as a symbol of fertility.
Many paintings of Venus, the Roman goddess of love and fertility, included a scallop shell in the painting to identify her. This is evident in Botticelli's classically inspired The Birth of Venus (which has even been nicknamed "Venus on the half-shell").
Alternatively, the scallop resembles the setting sun, which was the focus of the pre-Christian Celtic rituals of the area. To wit, the pre-Christian roots of the Way of St. James was a Celtic death journey westwards towards the setting sun, terminating at the End of the World (Finisterra) on the "Coast of Death" (Costa de Morta) and the "Sea of Darkness" (ie, the Abyss of Death, the Mare Tenebrosum, Latin for the Atlantic Ocean, itself named after the Dying Civilization of Atlantis). The reference to St. James rescuing a "knight covered in scallops" is therefore a reference to St. James healing, or resurrecting, a dying (setting sun) knight. Similarly, the notion of the "Sea of Darkness" (Atlantic Ocean) disgorging St. James' body, so that his relics are (allegedly) buried at Santiago de Compostella on the coast, is itself a metaphor for "rising up out of Death", that is, resurrection.
The scallop shell symbol found its way into heraldry as a badge of those who had been on the pilgrimage to Compostela, although later it became a symbol of pilgrimage in general. Winston Churchill's family coat of arms includes a scallop, another example is the surname Wilmot and also John Wesley's (which as a result the scallop shell is used as an emblem of Methodism). However, charges in heraldry do not always have an unvarying symbolic meaning, and there are cases of arms in which no family member went on a pilgrimage and the occurrence of the scallop is simply a pun on the name of the armiger, or for other reasons.
In design, scalloped edges or ridges refers to a wavy pattern reminiscent of the edge of a scallop's shell.