A new fossil boring sponge, Aka robinsoni, is described from the shallow-water Middle Eocene Somerset Formation, White Limestone Group, Jamaica. This new species, preserved in its boring in the foraminifer Lepidocyclina sp., complements the meager sponge record of the White Lime-stone Group from which there have been only two previous recordings, both from deep-water carbon-ate deposits of the Montpelier and Pelleu Island for-mations. In addition, it also complements the few known Aka spp. from the Tertiary.