Form: Polymorphic sheets, thin cushions to branching-repent, with the branches frequently anastomosing. Grows from a basal crust which may spread across rocks.

Colour: Orange, beige, light brown. Boundaries between colour zones are typically sharp, a useful diagnostic character.

Smell: None.

Consistency: Hard, brittle, incompressible. Feels like a stick of wood.

Surface: Smooth.

Apertures:

• Oscules are regularly scattered along the branches, usually on small 'mounds'.

Contraction:

• None.

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Synonyms: See de Weerdt, 1986 for list (many).

Internal characters

Skeleton: Surface skeleton is very regularly reticulated, unispicular; the interior is a dense polyspicular network, with considerable amounts of spongin present, especially at the nodes of the net.

Spicules: Short, fat oxea 120-150 x 5-12 μm.

Identity: The hardness, repent branching, neat arrangements of oscules which remain open when sponge is preserved, together with a typically Haplosclerid skeleton are, taken together, fairly distinctive.

Distribution Map from NBN: Haliclona simulans at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Haliclona simulans at iNaturalist World Species Observations database.

WoRMS: Haliclona simulans at World Register of Marine Species. Accepted name: Haliclona (Haliclona) simulans (Johnston, 1842). AphiaID: 132858.

Classification: Biota; Animalia; Porifera; Demospongiae; Heteroscleromorpha; Haplosclerida; Chalinidae; Haliclona

Voucher: BELUM : Mc1419. Brittany, France.

Editors: D. Moss, B.E. Picton.