Aplysiida

The order Aplysiida, commonly known as sea hares (Aplysia species and related genera), are medium-sized to very large opisthobranch gastropod molluscs with a soft internal shell made of protein.Some young sea hares seemingly are capable of burrowing in soft sediment, leaving only their rhinophores and mantle opening showing.The toxic ink may be white, purple, or red, depending on the pigments in their seaweed food source and lightens in color as it spreads, diluted by seawater.[citation needed] In addition to the colored ink, sea hares can secrete a clear slime akin to that released defensively by hagfish which physically plugs the olfactory receptors of predators like lobsters.In the moving marine environment and without the sophisticated cognitive machinery of the cephalopods, their motion appears to be somewhat erratic, but they do reach their goals, such as the seabed, according to the wave-action, currents, or calmness of their area.[citation needed] Aplysia californica is a species of sea hare noteworthy for its use in studies of the neurobiology of learning and memory, due to its unusually large axons.
Sea hare Dolabella auricularia at Big Island of Hawaii
The Sea-HareDuffel bagAnaspidaAnapsidaAnaspididaeAplysia californicaScientific classificationEukaryotaAnimaliaMolluscaGastropodaHeterobranchiaEuthyneuraTectipleuraP. FischerAkeroideaAkeridaeAplysioideaAplysiidaeSynonymsAplysiaopisthobranchgastropodmolluscsmarinecommon namedirect translationrhinophoresPaul Henri FischerJohannes ThieleTaxonomy of the Gastropoda (Bouchet & Rocroi, 2005)mantleradulaAplysia vaccariahermaphroditicparapodiaDolabella auriculariaseaweedcamouflageshagfishjet propulsioncephalopodsChineseHawaiineurobiologylearningmemoryNobel LaureateEric Kandelaplysia gill and siphon withdrawal reflexAplysia dactylomelaBMC Evolutionary BiologyYouTubeWikispeciesCabrillo Marine AquariumWikidataOpen Tree of Life