The Fine Structure of Haematolœchus Spermatozoan Tail

For a n u m b e r of year~ investigators generally agreed that electron optical studies had established a basic pattern for the axial fiber bundle of sperm tails. This consisted essentially of two single ilia-ments centered within a ring made up of nine doublet filaments. It was further established that this structure possessed bilateral symmetry, All of the electron micrographs are from spermatozoa of the flatworm Haernatolvechus medioplexus fixed in 1 per cent veronal-buffered osmium tetroxide. The micrographs were taken at an instrumental magnification of 9,500 and were further enlarged photographically. FIOURE 1 Cross-section through a sperm tail to show the general configuration of the axial fiber bundles. The single central unit with its core (1), cortex (2), and sheath (3) ; the peripheral doublet filaments and the radial spokes (5') can be observed. The arrows (RF) indicate possible connections between the rim elements. >(166,000.