The Probable Method of Fertilization in Terrestrial Hermit Crabs Based on a Comparative Study of Spermatophores

ALTHOUGH the physiological and mechanical phenomena of the vasa deferentia resulting in the elaboration of the spermatophores of marine hermit crabs (Pagurida) have been investigated (Mouchet, 1931; Matthews, 1953), these phenomena in terrestrial hermit crabs (Coenobita and Birgus) have been neglected. Spermatophores of marine hermits are made with precision; the so-called immutable form of their acuminate capsules is often distinctive of the species. These capsules, "elevated" on slender stalks, are admirably adapted for aquatic dissemination of the spermatozoa. Because marine hermit crabs are regarded as the progenitors of terrestrial hermit crabs, the present· study was undertaken to reveal whether the form of the aquatic spermatophore has become modified in the change to a terrestrial environment, and if so, to consider, in lieu of actual observation, whether these modifications are of sufficient magnitude to make tenable the common assumption that in terrestrial hermits fertilization occurs on land.