Geodia macandrewi Bowerbank (1872) is a whitish massive sponge that may be globular, but more frequently irregularly lobate or forming an inverted cone with flattened top. It is similar in shape, size and surface characteristics to G. barretti, but microscopically these two species may be easily distinguished by the size of the sterrasters (> 250 µm in this species, whereas G. barretti has sterrasters < 100 µm). Deep water.
Colour: off-white to cream-yellow outside, pale yellow or beige inside.
Shape, size, surface and consistency: Massive, often globular, but usually not perfectly rounded such as G.barretti. Shape in larger specimens (1 m diameter or more) tends toward an inverted cone with flattened top. Consistency hard, but easily damaged or broken. Rough to the touch. Inside pulpy. Pores arranged in sieves overlying incurrent depressions ('chones'). Oscules small, 0.5 mm.
Spicules: Megascleres: Oxeas of the cortex up to 350 µm, of the choanosome several mm; dichotriaenes up to 7.3 mm x 110 µm, protocladi up to 500 µm, deuterocladi up to 320 µm; protriaenes several mm in length x 38 µm in thickness, cladi 175 µm; anatriaenes up to 9 mm, cladi up to 180 µm. Microscleres: Sterrasters spherical to elliptic, up to 270 µm diameter; spherasters in two categories, 6.5 µm and 25 µm.
Skeleton: Radiate. A cortex of 3.5 mm consisting of sterrasters, small spherasters and cortical oxeas, carried by dichotriaenes and protriaenes, and pierced by choanosomal oxeas. Pulpy choanosome a confused mass of oxeas and spherasters.
Distribution: Norway, Faroes, British Isles, France, Arctic.
Ecology: Deep water on boulders and coldwater corals, below 180 m.
Etymology: named after the British spongologist Macandrew.
Type specimen information: The type is in the Natural History Museum, London.
Easily distinguished from most other European Geodiidae by the large size of the sterrasters.
Source: Sollas, 1888.