Whelk, a marine, univalve, gasteropod shell, of the genus duecinum (Linn.). There are about 20 living species, and more than 100 fossil in the miocene formations. The shell is ovate-conic, the aperture having a notch without a canal, and the pillar not flattened and somewhat twisted. The common whelk, or buckie (B. undatum, Linn.), is the largest, being about 3 in. long, grayish or brownish white, with numerous raised lines and stria); it is very common on the coasts of Great Britain, where it is dredged as an article of food; it is found from low-water mark to a depth of 100 fathoms, and is distributed through the Irish, North, and Arctic seas, along the American shore from Cape Cod to Greenland, and across to the Siberian and Okhotsk seas; it is found fossil in the newer pliocene of Sicily, though not now living in the Mediterranean. The most common species on the Atlantic coast of America is the B. obsoletum (Adams), ovate, reddish or olive brown, with a network of lines, aperture dark violet, with six whorls and apex generally eroded; it is about an inch long and half an inch wide; the animal is mottled with slate color.

Its movements are very active, and its food consists of dead crabs, fish, etc.; it prefers muddy, still inlets, flats uncovered at low tide, and the mouths of brackish rivers.