Description

 Diodora graeca has an oval-shaped, conical shell that is up to 4 cm in length. The tip of the shell bears a characteristic rounded hole, used for respiration, which is tipped forward and positioned towards the front of the shell. The surface of the shell is marked with 20-30 ridges that radiate outwards from the apex and give a convoluted appearance to the edge of the shell. In the grooves between these ridges are smaller ridges. The colour of the shell is usually white or grey but may be yellow, orange or red, and is marked with bands of brown or green radiating from the apex. The body comprises a large head, oval-shaped foot and a thick mantle. The base of the head bears two tentacles each with a lateral eye-stalk. The foot is surrounded by a ring of 30-35 well-developed tentacles that alternate between being long and short. The mantle is large enough to fall below the edge of the shell and covers the sides of the foot and bears wart-like papillae on its surface. An extension of the mantle protrudes from the apical hole forming a short, inhalant siphon. The body is coloured red, yellow, orange or white with darker spots.Diodora graeca feeds on sponges, particularly Hymeniacidon and Halichondria, by the scraping action of its radula. This species is gonochoristic and reproduces through December to May by external fertilization. The young develop in egg capsules and hatch as juveniles, hence there is no free larval stage.