(Dalyell, 1848)
Description
Diameter of base up to 30 mm, span of tentacles to 40 mm. Occasionally much larger individuals may be encountered, these are usually hexamerous and may be specimens that have never reproduced asexually.
Base wider than the column, closely adherent and difficult to detach from the substratum without tearing; its outline is usually ragged due to basal laceration. Column moderately tall in expansion, flaring out trumpet-like toward the disc. Suckers usually prominent, largest on the distal part of the column and fading away proximally; only exceptionally do they have gravel or other debris stuck to them. Cinclides, just visible as dark dots, are present on the upper part of the column and just above the limbus; acontia are emitted from them freely.
Tentacles: Moderate or long, usually irregularly arranged but occasionally hexamerous, up to about 200.
Colouration: Column variable in colour: red, orange, brown, whitish or pale grey-green. The suckers form pale whitish spots, usually prominent but sometimes indistinct on specimens with pale columns. The general colour is palest on the proximal part, which often bears paler longitudinal stripes, becoming richer and darker distally. Five colour varieties are recognized, based on the colouration of the disc and tentacles; these are usually fairly distinct but intergrading forms are not uncommon.
Var. miniata: Ground colour of disc variable, often variegated - orange, red, grey, brown, cream, etc. - typically shading to orange around the margin. Always with a well-marked dark pattern, but often varying in detail. Tentacles similar to disc, usually banded and sometimes with a pair of dark longitudinal lines.
A common variant has a rayed effect, caused by alternate segments of the disc being light and dark in colour; these segments may be regular or irregular and may or may not affect the related tentacles. A similar effect is frequent in Sagartia troglodytes and Cereus pedunculatus. A further distinctive variation possesses an opaque white ring around the mouth, which may also occur in S. troglodytes.
Var. rosea: Disc variably coloured, plain, or patterned as in miniata; tentacles pink, rose-red or magenta.
Var. aurantiaca: Disc usually greyish, sometimes with traces of the typical pattern; tentacles dull orange. This variety resembles a common variety of S. troglodytes and care should be taken not to confuse the two.
Var. venusta: Disc plain orange, varying from pale and translucent to a rich, opaque colour; tentacles white.
Var. nivea: Disc and tentacles plain white, usually translucent.
Sagartia elegans habitually and frequently reproduces by basal laceration but longitudinal fission has also been observed on one occasion, in an aquarium.
Nematocysts of acontia: p-mastigophores 39-80 x 4.0-9.0 µm, b-mastigophores 24-44 x 2.6-5.0 µm.
Habitat
On the shore in pools, under stones, in caves or beneath overhangs, from about MTL downward. Also common in the sublittoral down to about 50 m. This species is commonly encountered with its base inserted into a hole or crevice in the substratum into which it can withdraw when disturbed. In localities where the rock is riddled with piddock holes, S. elegans may be very abundant, forming large and colourful aggregations whose individuals occupy every suitable hole and crevice. When deserted by the tide, specimens are often found hanging from cave roofs in a semi-expanded state, but when touched they withdraw deep into the rock. Rarely found in muddy or sandy substrata, where S. troglodytes and Cereus may be abundant, but occasionally, usually large specimens may be found in this situation. In some sublittoral localities specimens are often abundant, attached to the open rock surface.
Distribution
Common and locally abundant on all coasts of the British Isles, extending around south-west Europe to the Mediterranean, and northward to Iceland and Scandinavia. Var. miniata is probably the most widespread variety but only aurantiaca may be considered rare, being known only from South Wales and Devonshire.