Nannonyx goesii Sars, 1890 – synonym of Nannonyx goesi
Naupredia tristis van Beneden, 1861 – synonym of Phtisica marina
Nautilograpsus minutus Hodgson, 1896 – synonym of Planes minutus
Necora puber Holthuis, 1987 – synonym of Necora puber
Nematopus elegans G.O. Sars, 1863 – synonym of Erythrops elegans
Nematopus goësii G.O. Sars, 1866 – synonym of Erythrops erythrophthalma
Nemertes nesaeoides White, 1847 – synonym of Chelura terebrans
Neomysis vulgaris (J.V. Thompson, 1828) – synonym of Neomysis integer
Neopleustes bicuspis Stebbing, 1906 – synonym of Parapleustes bicuspis
Nicea lubbockiana Bate and Westwood, 1861 – synonym of Hyale pontica
Nicea prevostii Bate, 1862 – synonym of Hyale prevosti
Niphargus elongatus Boeck, 1871 – synonym of Eriopisa elongata
Noenia excavata Bate, 1862 – synonym of Gammaropsis nitida
Noenia rimapalmata Bate, 1862 – synonym of Gammaropsis nitida
Noenia tuberculosa Bate, 1862 – synonym of Gammaropsis nitida
Noenia undata Bate, 1862 – synonym of Gammaropsis nitida
Nototropis falcatus Stebbing, 1906 – synonym of Atylus falcatus
Nototropis guttatus Costa, 1857 – synonym of Atylus guttatus
Nototropis swammerdami Stebbing, 1906 – synonym of Atylus swammerdami
Nototropis vedlomensis Stebbing, 1906 – synonym of Atylus vedlomensis
Nyctiphanes (?) latifrons Illig, 1908 – synonym of Nyctiphanes couchi
Nyctiphanes couchii Norman, 1892 – synonym of Nyctiphanes couchi
Nyctiphanes norvegica G.O. Sars, 1883 – synonym of Meganyctiphanes norvegica