Spermiogenesis of Eledone cirrhosa Lamarck (Cephalopoda, Octopoda)

Spermiogenesis in a mature male Eledone cirrhosa has been studied by means of phase contrast and electron microscopy. Material from the testis was either studied alive or by means of thin sections. Material from the vas deferens and spermatophores was either studied live, in thin sections or in negatively stained preparations for the electron microscope. The spherical spermatid cells each become modified to give an elongate mature gamete. The gamete is remarkable in the size and complexity of its spiral head, the small size of the mid-piece and the length of the sperm tail. The acrosome is simple but helical. The flagellum originates in a single centriole; the 'proximal' centriole is lost. The axial filament consists of a 'normal' 9+2 microtubular system together with 9 accessory $\gamma $ fibres; the $\gamma $ fibres form a centriolar ring at their point of origin. Cytochemical tests show that there is a loosely packed deposit of glycogen throughout the length of the tail. There are no glycogen deposits within the mid-piece or the head.