Nembrotha chamberlaini 
Nembrotha livingstonei 
Nembrotha mullineri 
Nembrotha purpureolineolata 
Nembrotha yonowae 
Nerita versicolor 
Nesiohelix swinhoei 
Ninja Slug 
Northern abalone 
Notobryon wardi 
Notodoris minor 
Notodoris serenae 
Novisuccinea ovalis 
Obba listeri 
Ocellate Phyllidia 
Odontoglaja guamensis 
Okenia brunneomaculata 
Okenia nakamotoensis 
Oliva keenii 
Oospira penangensis 
Opalescent Sea Slug 
Opisthoporus biciliatus 
Orange-banded Arion 
Oregon forestsnail