Description: This sponge is greyish-beige in colour and consists of a single tubular structure with a hairy appearance. The tube is attached to the substratum at one end and open at the other. A crown of spicules surrounds the open end. The sponge can be over 14 cm in length, individuals of this length have only been observed in marinas and it is unclear whether this growth form is due to the sheltered environmental conditions within marinas and harbours or whether it represents a separate species, perhaps non-native in origin.

Habitat: This growth form has only been reported from marinas and harbours where it grows attached to artificial substrata such as oyster cages.

Distribution: Data deficient. In Northern Ireland this form has been recorded from Belfast Lough and Glenarm Marina, Co. Antrim. There are also reports of it from marinas on the south coast of Britain.

Similar Species: May be confused with other Sycon species and Grantia compressa however Grantia is flattened not tubular, has a smooth surface and lacks the crown of spicules.

Key Identification Features:

• Tubular sponge.
• Relatively long length, up to 14 cm.
• Hairy surface.
• Crown of spicules.

iNaturalist: Sycon "large" at iNaturalist World Species Observations database.