The dog whelk, dogwhelk, or Atlantic dogwinkle (Nucella lapillus) is a species of predatory sea snail, a carnivorous marine gastropod in the family Muricidae, the rock snails. Nucella lapillus was originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Buccinum lapillus (the basionym). "Dog whelk" can also refer to the Nassariidae. Distribution This species is found around the coasts of Europe and in the northern west Atlantic coast of North America. It also can be found in estuarine waters along the Atlantic coasts. This species prefers rocky shores, where it eats mussels and acorn barnacles. Shell description The dog whelk shell is small and rounded with a pointed spire and a short, straight siphonal canal (a groove on the underside of the shell) and a deep anal canal. The overall shell shape varies quite widely according to the degree of exposure to wave action of the shore on which a particular population lives but the body whorl (the largest section of the shell where the majority of the visceral mass is located) is usually around 3/4 of the total length of the shell. The aperture is usually crenulated in mature dog whelks, less often in juveniles. The shell surface can be fairly smooth interrupted only with growth lines, or when the snail is living in more sheltered areas the shell surface can be somewhat rough and lamellose. The surface is spirally corded. The outer lip is dentate and ridged within. The columella is smooth. The external shell colour is usually a whitish grey, but can be a wide variety of orange, yellow, brown, black, or banded with any combination of these colours. They can even, occasionally, be green, blue, or pink. Ecology Habitat The dog whelk lives on rocky shores, and in estuarine conditions. Climatically it lives between the 0 °C and 20 °C isotherms. Effects of the habitat Wave action tends to confine the dog whelk to more sheltered shores, however, this can be counteracted, both by adaptations to tolerate it such as the shell and muscular foot, and by the avoidance of direct exposure to wave action afforded by making use of sheltered microhabitats in rocky crevices. The preferred substrate material of the dog whelk is solid rock and not sand, which adds to its problems at lower levels on the shore where weathering is likely to have reduced the stability of