pluteuses (pl) 1. The free-swimming, bilaterally symmetrical larva of an echinoid or ophiuroid. 2. The free-swimming larva of sea urchins and ophiurans, having several long stiff processes enclosing calcareous rods. Word families with similar applications about: 'swim, swimming': ... Found on http://www.wordinfo.info/words/index/info/view_unit/3366/