Linné, 1758
Description:
Body is broadly oval, maximum mantle length is 400 mm. Dorsal anterior edge of mantle developed as a blunt, rounded lobe. Fins are starting directly at the anterior edge of the mantle and they are extending beyond the edge noticeably, reaching anteriorly to level of posterior edge of eyes; fins widen at posterior part of the mantle. Arms are relatively short, comprising less than half of the combined length of head and arms; arms have four rows of suckers; central pair of arms is broadly flattened dorso-ventrally; all arms have acute outer edges.
There are 5 longitudinal rows of conspicuously unequal club suckers, 5-7 suckers of the median row being clearly larger than others (S. officinalis-photo).
The internal shell has a spine, outline is elongate-oval, almost parallel-sided (may be slightly concave on sides) and smoothly rounded posteriorly. Posterior part of shell is widened, edges of outer cone are wide. Shell width in males is 30-40 % of shell length, in females 33-42 %.
Habitat:
Shallow sublittoral, and offshore to 250 m. Common inshore during summer months.
Distribution:
Widely distributed. From the Shetland Islands, southern Norway and southern part of the North Sea to the Cape of Good Hope and along south-eastern coasts of Africa and Mozambique. Abundant on all British coasts (Distr. S. officinalis).