ORTON1 suggested that protandrous animals might be self-fertilizing and that this would be advantageous for the spread of a species. He concluded that Crepidula fornicata was self-fertilizing because he found an isolated female guarding veliger larvae. I have kept single Crepidula in aquaria and they have laid fertilized spawn two to three months later. Chipperfield2 found no unfertilized eggs but he examined only unbroken chains from a densely populated area. Wilczynski3 has recently said that the typical chains are feeding communities, not breeding associations and that copulation is effected with additional or visiting males. In Calyptraea chinensis (L.) males and females begin to associate seven months before spawn is laid4. Females probably store foreign sperms for long periods. Evidence for self-fertilization in Crepidula is therefore still lacking.