Rissoina spirataRissoina spirata, the spiral risso, is a species of small sea snail, a marine gastropod mollusc or micromollusc in the family Rissoinidae.DescriptionThe size of the shell varies between 7 mm and 15 mm.DistributionThis species occurs in the Red Sea, in the Indian Ocean off Madagascar and the Aldabra Atoll; in the Central Pacific; in the Mediterranean Sea.