FINE STRUCTURE OF SPERMATOZOA OF THE HAGFISH EPTATRETUS BURGERI (AGNATHA)

摘要

Live motile spermatozoa of the hagfish Eptatretus burgeri were obtained for the first time, and their fine structure was examined. The spermatozoon is characterized by an extremely long midpiece, Two of the four midpiece mitochondria are extensively elongated and extend through almost the entire length of the tail. The acrosome contains electron-dense and less dense materials in two different compartments, Amorphous subacrosomal material lies between the acrosome and the nucleus. No distinct perforatorium rod or filamentous structure was observed within the subacrosomal material, Two centrioles lie almost end to end in the nuclear fossa near the posterior end of the nucleus. The structure of the acrosomal complex in the hagfish, which is quite different from that in the lamprey, was compared to that of other chordates with respect to its function in sperm-egg interaction and phylogeny.