Description: Thin sheet forming extensive patches on rock surfaces or on other sponges (e.g. Stelletta grubii). Orange-red. Fairly tough sheet, which holds together well when scraped off. Oscules inconspicuous, scattered, irregular in shape and size. Excurrent channels are generally conspicuous, converging on the oscules and forming irregular stars.

Habitat: Vertical or steeply inclined rock faces in both sheltered and exposed places. May be on other sponges such as Stryphnus ponderosus and Stelletta grubii.

Distribution: "South coast of England; France; Spain; Mediterranean etc." Known recently from Lough Hyne, Co. Cork; W. Anglesey; Skomer; N. Cornwall; Jersey; Guernsey.

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

iNaturalist: Antho inconstans at iNaturalist World Species Observations database.