Form: Stipitate, the stalk bearing a roughly ovoid, sometimes slightly flattened, body, consisting of a network of thin walled anastomosing tubes. Maximum height 3cms, although specimens are frequently less than half this size.

Colour: White, off white.

Smell: None. Slime : None.

Consistency: "Firm to soft"; even tough and resilient.

Surface: In macro view, the sponge surface is even. The surfaces of the individual tubes are smooth.

Apertures:

• A single oscule (?sometimes more) borne at the apex of the sponge.

Contraction:

• Not noticeable.

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Synonyms: Leucosolenia lacunosa (Bean in Johnston, 1842). This species was regarded by Burton (1963: 183) as being one of several "Named Forms" comprising Clathrina coriacea (Montagu, 1818) which he accepted as the valid name for the whole complex.

Internal characters

Skeleton: The skeleton consists of triradiates distributed throughout the body, with diactinal spicules occurring at the base of the body, and in the stalk.

Spicules: The triradiates are of two types: (a) with rays of equal length, 80-300 μm; (b) sagittal triradiates with the basal ray (90-600 μm) longer than the two paired rays (60-300 μm). The latter paired rays may exhibit abnormalities. The diactinal spicules (oxea) (c) are 80-300 μm long. The growth point is normally marked by a central irregularity.

Identity: The external form ("like a Clathrina coriacea on a stalk") is characteristic.

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

iNaturalist: Clathrina lacunosa at iNaturalist World Species Observations database.

WoRMS: Clathrina lacunosa at World Register of Marine Species. Accepted name: Clathrina lacunosa (Johnston, 1842). AphiaID: 150239.

Classification: Biota; Animalia; Porifera; Calcarea; Calcinea; Clathrinida; Clathrinidae; Clathrina

Editors: D. Moss.