Grantia capillosa (Schmidt, 1862) is a hispid, whitish or yellowish, tubular calcareous sponge of fairly big size (> 5 cm high, 2 cm in diameter). It is a southern species recorded from the west coasts of the British Isles and France.
Colour: White, yellow or grey alive.
Shape, size, surface and consistency: Fairly big, hairy tubes, unstalked. Size up to 5 cm or more high, 2 cm in diameter. Terminal oscule with naked rim or very short fringe. Surface hispid due to projecting spicules. Consistency fragile.
Spicules: (Grantia capillosa spics) Calcareous. Ectosomal triactines subregular, rays: 80-350 x 6-20 µm; tubar triactines sagittal: paired rays: 40-400 x 5-28 µm, basal ray: 40-400 x 5-28 µm; choanosomal triactines sagittal, paired rays: 100-250 x 6-20 µm, basal ray: 150-390 x 10 µm; atrial triactines sagittal, paired rays: 100-150 x 10 µm, basal ray: 200 x 8-16 µm; atrial tetractines similar to triactines, with apical ray: 100-200 x 10 µm; ectosomal oxeas in two size categories: 1000-10, 000 x 20-40 µm and 200-500 x 2-5 µm.
Skeleton: Ectosomal skeleton a tangential layer of triactines with oxeas projecting beyond the surface; tubar skeleton consisting of basal rays of the choanosomal sagittal triactines and several rows of triactines; atrial skeleton consisting of paired rays of the choanosomal triactines and a tangential layer of tetractines and triactines.
Ecology: On hard bottoms without sediment, 10-45 m.
Distribution: W Ireland, Plymouth, Roscoff; Mediterranean.
Etymology: capillus (Latin) = hair, referring to the condition of the surface.
Type specimen information: Several type specimens are in the Natural History Museum, London, BMNH 1867: 7:26:46, 49, 93, 95 (dry). Slides: BMNH 18184.108.40.206a.
The size and hairiness of this species make it fairly easy to recognize.
Source: Burton, 1963.