Geodia simplicissma Burton (1931) is known only from a few fragments from Northern Norway. The difference with the more common G. barretti and G. cydonium is microscopical: it has an ectosomal palisade of small oxeas lying peripheral to the crust of sterrasters.
Shape, size, surface and consistency: Known only from a few fragments, so no details of the habit are known.
Spicules: Megascleres: Huge oxeas: 2200 x 32 µm; "microxeas" (= cortical oxeas): 250 x 4 µm; orthotriaenes: shaft 1700 x 48 µm, cladi 320 µm; a single anatriaene with cladi of 150 µm was found. Microscleres: Sterrasters, spherical: 70 µm; pycnasters: 4 µm.
Skeleton: (Geodia simplicissima skel) Ectosomal: a palisade of microxeas is erected on the sterraster layer, which in its turn is carried by the cladi of the orthotriaenes. Choanosomal: radial bundles of oxeas and orthotriaenes.
Ecology: In fjords, 10-75 m.
Distribution: Northern Norway.
Etymology: The name presumably refers to the relatively simple spicule complement.
Type specimen information: The type is in the Natural History Museum, London: BMNH 1922.214.171.124 (3 slides).
The description is unsatisfactory and the specific distinctness is doubtful.
Source: Burton, 1931.