(Norman, 1868)
Description
Form of colonies and their variations similar to P. axinellae; polyps generally larger, up to 25 mm tall and 8 mm diameter. The encrustation of sand grains, sponge spicules, and foraminiferan shells is variable in extent; where encrustation is sparse the texture of the column is grainy, resembling the skin of an orange.
Tentacles: Proportionately shorter than in P. axinellae, 34-44, typically 40-42.
Colouration: Colouration of whole colony whitish, sometimes tinted with buff or pink, the latter due to ripe gonads. Preserved specimens often become yellowish or reddish brown.
Nematocysts: The holotrich nematocysts of the ectoderm occur in two size ranges: 40-53 x 19-25 µm and 23-35 x 13-19 µm.
Habitat
This species has been recorded encrusting sponges, worm tubes, corals (Genus Lophelia) and stones. Generally occurring in deep water down to at least 400 m but also found in shallow coastal waters, c. 20 m.
Distribution
Occurs in many parts of the north-east Atlantic, probably widespread in deep water off the continental shelf; recorded in British waters from western Ireland, western and northern Scotland.