Spermatozoa of two Eledone species (Cephalopoda, Octopoda)

Spermatozoa from testes and spermatophores of two octopod species, Eledone cirrhosa and E. moschata, have been investigated by electron microscopy. At the base of the mature sperm acrosome of both species a well developed, periodic, conical structure is present. This structure is strikingly similar to that present in the Octopus sp. acrosome. Also the modalities of formation of such a structure during spermiogenesis show strong similarities between the Octopus and Eledone genera. The resistance to disruption of sperm chromatin of E. cirrhosa and E. moschata after treatments with SDS and mercaptoethanol which are known to dissolve disulfide-bridges, reveals the presence of S-S crosslinks.