Thallus a spongy sphere with a velvety soft, shiny surface; becoming more flattened when increasing in size. The internal branched filamentous network becomes looser with increasing size of the sphere, the space fills with water and the surface becomes indented. Anchored to substratum by felted filaments (Braune & Guiry, 2001). 

Original publication: Agardh, C.A. (1817). Synopsis algarum Scandinaviae, adjecta dispositione universali algarum. pp. [i]-xl, [1]-135. Lundae [Lund]: ex officina Berlingiana.

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NE Atlantic (Ireland to Canary Is); Mediterranean. 

Videolink for specimens from Ibiza (Balearic Islands, Spain)

http://youtu.be/ZAm9ojVbJi8

Brodie, J., Maggs, C.A. & John, D.M. (2007). Green seaweeds of Britain and Ireland. pp. [i-v], vi-xii, 1-242, 101 figs. London: British Phycological Society.

Burrows, E.M. (1991). Seaweeds of the British Isles. Volume 2. Chlorophyta. pp. xi + 238, 60 figs, 9 plates. London: Natural History Museum Publications.

Basionym: Lamarckia bursa Olivi

Taxonomic notes: According to Silva (Index Nominum Algarum), Alcyonium bursa Linnaeus is traditionally cited as basionym of Codium bursa but is invalid in botanical nomenclature.