is usually 7 cm long but can grow to 20 cm in length. The body is long and narrow and the parapodia join rather high posteriorly. At the front of the body the anterior tentacles are short, with rounded extensions to the mouth slit while the tentacles on the head (rhinophores) are long and slender. It produces both purple and white secretions when disturbed. The mantle has a large opening (foramen) through which the internal shell may be seen. The internal shell is around 4 cm in length and is transparent and pale amber in colour.The body colour of Aplysia punctata
is said to vary with the character of its algal diet. Therefore, juveniles that feed on red algae are red, whereas the adults, which are said to migrate on shore to breed are brownish or greenish in accordance with their diet (e.g. Ulva
). It is similar to Aplysia fasciata
which is larger and can reach lengths of 40 cm, it is also dark brown or black in colour. The eggs are pink and laid in tangled threads.