Venus's Girdle, a transparent sea animal found in the Mediterranean and the Atlantic. It is iridescent in sunlight and luminescent at night. The flat, ribbon-shaped animal is about four feet (120 cm) wide and only two inches (5 cm) long. The mouth is located in the middle of the body, opposite a sensory organ that helps the animal maintain equilibrium. The body is filled with a jellylike substance called mesoglea, which keeps it buoyant. The body is fringed with eight bands of comblike plates, called ctenes, which move like paddles, helping the animal swim.

Venus's girdle is Cestum veneris of the family Cestidae. It belongs to the comb jelly phylum, Ctenophora.