limb used for swimming
nectopod In zoology, a limb (as of a mollusk) adapted for swimming or a swimming organ. Word families with similar applications about: 'swim, swimming': nata-; neusto; pleo-. Inter-related cross references, directly or indirectly, involving the 'sea' and the 'ocean' bodies of water: ab...
(in certain mollusks) an appendage modified for swimming.