tectus nilotitus or rochia nilotica operculum on white

french polynesia animal aquatic beautiful biology calcareous calcium cephalopod chiton columella conchology ecology ecosystem environment food gastropod hermit indian indopacific invertebrate isolated life linne marine mollusc mollusca mollusk natural nature nilotitus ocean operculum pacific seashell rochia nilotica sea shell snail horseshoe snails tahiti tectus tegulidae underwater wildlife white