Size up to 400 mm. Large sea slug presenting the typical, wing-like parapodia that are characteristic of the genus Aplysia. Internal shell present. Color dark-brown, blackish, sometimes with darker lines. Sea hares are active swimmers using the parapodia to perform wing-like motion, and are voracious macro-herbivores, consuming large quantities of sea weed on a daily basis. Eggs are laid in long, gelatinous, orangish strings that form tangled masses (additional image). This species may be distinguished from the Mottled Sea Hare, Aplysia fasciata Poiret, 1789 by, among other features, the darker coloration and larger size. The sea hare in the photo was collected by R. Mensch in February 2017.