Life history of Intertidal Gastropod Species Planaxis sulcatus (Born,1778) (Gastropoda; Planaxidae) in Hakamagoshi, Sakura-jima Isaland, Kagoshima, Japan

Planaxis sulcatus (Born,1778) belonging to the Planaxidae is a tidal snail, is distributed along the west coast of the Pacific Ocean from Honshu to Kyushu, Japan. Seasonal change in the the pattern of internal growth of the shell of this species were investigated in a tidal zone of Sakurajima, Kagoshima, Japan. Shell samples were collected monthly from Decmber 2021 to November 2022 in the tidal flat along the Sakurajima coast of Sakurajima in Kagoshima Bay. Frequency distributions of shell size showed that newly juveniles appeared in spring. This species matures in the second year Growth of shell stops in individual with Lip formation.