Weird Science #14

A group of space explorers land on the planet Gastropodia and meet the locals. Commander Morrison falls in love with the beautiful Luwana and decides to stay behind to marry her as his crew leaves for Earth. He wonders why the inhabitants of the planet all have special igloo like shells they dart into when frightened. He later learns that they are a species of humanoid hermaphroditic snails and to his horror Luwana changes genders into a male.