SPERMATOZOA AND SPERMIOHISTOGENESIS IN GRAPHIDOSTREPTUS SPEC (MYRIAPODA DIPLOPODA) .I. MATURE SPERMATOZOA

The mature spermatozoa of the African millipede Graphidostreptus spec. (Diplopoda) were studied by light and electron microscopy. The hat-like spermatozoa are combined two by two in spermatophores. They consist of a plate containing a disk-like nucleus, and a cylinder containing the acrosomal complex. - The free border of the hat and a basal layer below the caryoplasma are formed by a very electron-dense cytoplasma with hemispheric protrusions on the basal side. The basal cytoplasma contains light canaliculi with a diameter of about 100 Å. - There is no membrane around the caryoplasma which is composed of an electrondense substance. It is completely filled up with long and light canaliculi with a diameter of 400 Å. These canaliculi contain an electron-dense tubulus of about 200 Å diameter, in the axis of which a filament of about 40 Å diameter is to be found. - In the border of the nucleus on its dorsal side there is a circle of mitochondria. - The acrosomal complex building up the cylinder is composed of an envelope of striated material below the cell membrane, of a nail-like acrosomal vacuole, of a body appearing in section like a M, of a hemispheric calotte, and of a cristalloid lying in the center. © 1969 Springer-Verlag.