Appearance
Sea hares are mostly rather large, bulky creatures when adults. Juveniles are mainly unobserved on the shoreline. The biggest species, Aplysia vaccaria, can reach a length of 99 centimetres (39 in) and a weight of 14 kilograms (31 lb) and is arguably the largest gastropod species.
Sea hares have soft bodies with an internal shell, and like all opisthobranch molluscs, they are hermaphroditic. Unlike many other gastropods, they are more or less bilaterally symmetrical in their external appearance. The foot has lateral projections, or "parapodia".

