SPERMATOPHORE FORMATION IN TWO INTERTIDAL CRABS ALBUNEA SYMNISTA AND EMERITA ASIATICA (DECAPODA: ANOMURA)

¹ Unit of Invertebrate Reproduction, Department of Zoology, University of Madras, Madras—600 005, India

Decapod crustaceans employ spermatophores in sperm transfer. Anomura spermatophores are generally pedunculate and structurally species-specific. Spermatophores of the sand crabs Albunea symnista and Emerita asiatica are macruran-type. The A. symnista spermatophore is non-pedunculate, and comprised of a highly convoluted tube with a firm membrane forming a cord-like mass. This spermatophoric ribbon is embedded in a gelatinous matrix. In E. asiatica, the spermatophores are dimorphic and pedunculate, and are attached by the peduncle-end in a row on strands of membrane. The whole spermatophoric ribbon is further embedded in a jelly-like matrix. The histology of the inner epithelial cells of the vas deferens contributing to the spermatophore mass is described. Histochemical observations on the various secretory materials and their transformation to various spermatophoric components are reported. Mucopolysaccharides are the main component. The occurrence of pedunculate spermatophores in E. asiatica and their absence in A. symnista may reflect an interesting phylogenetic interrelationship, but the epizoic attachment of spermatophores and the probable mode of dehiscence are discussed in relation to the adaptive strategies of the two crabs to the precarious intertidal zone.