David Fleetham / Imperial commensal shrimp (Periclimenes imperator / Zenopontonia rex) on Spanish dancer nudibranch (Hexabranchus sanguineus) at night. Philippines.

Alex Mustard / Portrait of a nudibranch (Hypselodoris infucata) with orange-red rhinophores. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Tony Wu / Nudibranch (Cadlinella ornatissima), yellow with pink tipped tubercles and white rhinophores. Japan. March.

Alex Mustard / Nudibranch (Goniobranchus hintuanensis) portrait showing rhinophores. Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean.

Alex Mustard / Close up detail of the rhinophores and caruncle of a Nudibranch (Janolus savinkini). Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean.

Tony Wu / Nudibranch (Hypselodoris infucata) super macro close up of rhinophores, Lembeh Strait, North Sulawesi, Indonesia.

Alex Mustard / High magnification photo of Nudibranch (Nembrotha kubaryana), showing orange mouth parts and sensory rhinophores, and green gills (out of focus) Bitung, North Sulawesi, Indonesia. Lembeh Strait, Moluc...

Juergen Freund / Close up of rhinophores on Nudibranch (Halgerda sp) from Discodorididae family

David Fleetham / Aeolid nudibranch (Caloria indica) testing passing current with rhinophores for particles of food, Fiji, Pacific Ocean. 15M Depth.

David Fleetham / Close up of rhinophores of Scrambled egg nudibranch (Phyllidia varicosa), Hawaii, Pacific Ocean.

Alex Mustard / Detail of rhinophores and toxic lack markings on a Funeral nudibranch (Jorunna funebris). Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea, tropical west Pacific Ocean.