Form: Massive, lobed or encrusting.
Consistency: Firm, brittle, hard, breaks if bent.
Surface: Irregular in profile. There is a rough feel to it although it is not hispid.
Apertures: Oscules are few in number and found at the tops of lobes. They have raised rims but no collar of spicules, and may become subfistulose.
Contraction: None noticeable.
Skeleton: Ectosomal skeleton is a tangential layer of triradiates, with oxea which lie obliquely, without projecting beyond the surface. The skeleton of the chamber layer consists of irregularly arranged triradiates, occasionally quadriradiates. The endosomal skeleton is a tangential layer of quadriradiates which line the canals.
Spicules: Spicules are calcareous. The ectosomal triradiates (a) are symmetrical with rays 70-100Ám. The ectosomal oxea (b) are large and distinctively fusiform in shape, 400-600Ám long. Triradiates of the chamber layer (c) have rays 70-200Ám long and the endosomal quadriradiates (d) 100-120Ám.
Habitat: This species is mainly found in the infralittoral in clean water and seems to be uncommon.
Distribution: "British Isles; Atlantic coasts of France and Portugal." Probably confined to SW of the British Isles.
Distribution Map from NBN: Grid map (fast) : Interactive map (slower, requires login to view records) : National Biodiversity Network mapping facility, data for UK.
Identity: Distinctive in having a massive, lobed growth form rather than the tubular form of most Calcarea. The texture and white coloration combined with the calcareous spicules are characteristic.
Voucher: BELUM : Mc12. Padstow, N. Cornwall.
Editors: D. Moss, B.E. Picton.
|Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland |
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