Arhinophore is one of a pair ofchemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy insea slugs,marinegastropodopisthobranchmollusks such as thenudibranchs, sea hares (Aplysiomorpha), and sap-sucking sea slugs (Sacoglossa).
The name relates to the rhinophore's function as an organ of "smell".Rhino- meansnose fromAncient Greek ῥίςrhis and from its genitive ῥινόςrhinos. "Phore" means "to bear" fromNeo-Latin-phorus and from Greek -phoros (φορος) "bearing", a derivative ofphérein (φέρειν).
Rhinophores arescent ortaste receptors, also known aschemosensory organs situated on the dorsal surface of the head. They are primarily used for distancechemoreception andrheoreception (response to water current).[1]
The "scents" detected by rhinophores are chemicals dissolved in the sea water. The fine structure and hairs of the rhinophore provide a large surface area so that chemical detection is maximized.[2] This allows the nudibranchs to stay close to their food source (for example species ofsponges) and to find mates. In the sea hareAplysia californica, the rhinophores are able to detectpheromones.[1]
To protect the prominent rhinophores against nibbling by predators, including fish, most species of dorid nudibranchs are able to withdraw their rhinophores into a pocket beneath the skin.[2]
In reproductively matureAplysia adults, the rhinophore is about 1 cm in length.[1] The neuroanatomical organization includes a rhinophore groove where most of the sensory cells appear to be concentrated. Its sensoryepithelium containssensory neurons that projectaxons back to rhinophoreganglia anddendrites that end in either a surface-exposed cilium or a small protuberance.[1]
 Scale bar is 300 μm. rg - rhinophore groove tip - rhinophore tip. |  Scale bar is 100 μm. f - folds |  Scale bar is 10 μm. ci - numerous long cilia |
InA. californica, the oral tentacles, which are situated in a more ventral position, are possibly involved in contact chemoreception and mechanoreception.[1]
This article incorporatesCC-BY-2.0 text (but not underGFDL) from reference.[1]
