Abstract
Spermatophores consisting of a mass of mature sperm encapsulated within a solid, inflexible wall are described from five species of the genera Anisodevonia, Entovalva and Devonia, and obviously also occur in Cycladoconcha. The spermatophores are attached to the gill lamellae in the suprabranchial chamber in which these species brood the eggs. The ultrastructure of the monomorphic sperm of Anisodevonia ohshimai shows many similarities to the euspermatozoa of species of Pseudopythina and Barrimysia (families Kellidae and Montacutidae). Entovalva sp. A and sp. B Jenner and McCrary, 1967 are not related to any of the four studied genera.