(Philippi, 1837)
Seven Armed Starfish
Description
Body with a small disc and seven long arms, only tapering in the outer part; R/r: 7 to 8; up to 400 mm in diameter. Coloured brick-red or orange-brown.
Dorsal side
The upper surface is covered with paxillae. The upper marginal plates are replaced by marginal paxillae. There are three transverse series of lateral papillae which correspond to each two marginal paxillae. The papillae are many-lobed and are lacking only in the outer part of the arms. The lower marginal plates are well-formed and bear 4-5 spines. Across the dorsal side of the arm there are about 10 median paxillae.
Pedicellariae
There are bivalve pedicellariae on the marginal plates. The ventro-lateral plates sometimes bear trivalve pedicellariae.
Tube-feet
The tube-feet lack sucking disks, but bear double ampullae. The gut lacks intestine, pyloric caeca and anus.
Habitat
This species is found on sandy substrata, from about 4-400 m.
Distribution
In the North Sea this species is known from Yorkshire up to the Shetland Islands. Elsewhere it is found on the western British coasts and from the Faeroes to the Cape Verde Islands and the Mediterranean.