Bonellia

a genus of invertebrate animals of the class Echiuroidea of the subkingdom Articulata. There are several species, none of which are found in the waters of the USSR. The members of the species B. viridis have a sharply expressed sexual dimorphism. The body of the female is cylindrical (up to 7 cm long), and it has a long proboscis, divided into two parts at the end, which serves to grip soil along with bits of food (vegetable remains). A special pigment gives it a green color, which is protective. The body of the male is not more than 1–3 mm long and has a very simple structure. It lives as a parasite in the sexual ducts of the female; this fact was first discovered by the Russian scientist A. O. Kovalevskii in 1870. The species B. viridis is widely distributed in the coastal region of the Mediterranean Sea and in the Atlantic Ocean near the coast of Europe. It lives in shallow waters in the hollows formed in stones.