Lamarck, 1816
Description
Colouration
Test more or less high, usually subconical, not globular as in Echinus esculentus. Grows to about the same size as Echinus esculentus, at least to 15 cm horizontal diameter. Colour usually whitish, with a red-brown stripe along each series of plates. These stripes may be of varying breadth and the general colour becomes more whitish or reddish-brown. Spines usually reddish at the base, but with white points.
Buccal plates
Buccal plates carry only pedicellariae, no spines (E. acutus test).
Spines
Spines are rather scarce on the upper side. The primaries are conspicuously longer and more robust than the secondaries. The primary ones form conspicuous longitudinal series. Only every second or third ambulacral plate carries a primary spine.
Pedicellariae
Globiferous pedicellariae usually with only one lateral tooth on each side. The tridentate pedicellariae with long, slender blades, up to 2.5 mm long (E. acutus pedicellariae).
Habitat
A deep water species which is found till depths of nearly 1300m.
Distribution
On the east coast of the North Sea, the species is not known farther south than St Andrews. In the open North Sea it does not appear to occur south of the 100 m depth line. Elsewhere it is distributed from Bear Island in the north, to Cape Bojador and the Mediterranean in the south. It is not known from outside the N.E. Atlantic area.
Remarks
This species can form hybrids with Echinus esculentus.