Ianthina bicolour – synonym of Janthina janthina
Ianthina capreolata – synonym of Janthina exigua
Ianthina communis – synonym of Janthina janthina
Ianthina exigua – synonym of Janthina exigua
Ianthina fragilis – synonym of Janthina janthina
Ianthina nitida – synonym of Janthina exigua
Ianthina striata – synonym of Janthina exigua
Ianthina vinsoni – synonym of Janthina exigua
Ianthina violacea – synonym of Janthina janthina
Iasis zonaria – synonym of Soestia zonaria
Idotea angusta – synonym of Idotea chelipes
Idotea cretaria – synonym of Idotea granulosa
Idotea phosphorea – synonym of Idotea chelipes
Idotea salinarum – synonym of Idotea chelipes
Idothea irrorata – synonym of Idotea balthica
Idothea neglecta – synonym of Idotea neglecta
Idothea sexlineata – synonym of Idotea linearis
Idothea slabberii – synonym of Idotea balthica
Idothea tricuspidata – synonym of Idotea balthica
Idothea viridis – synonym of Idotea chelipes
Illex illecebrosus coindetiÊ – synonym of Illex coindetti