The neck is a short, slightly constricted segment of the sperm located between the base of the head and the first gyre of the mitochondrial helix of the mid-piece (Figs. 55 and 61) (Fawcett and Ito 1965, Zamboni et al. 1971, Fawcett 1975b, Phillips 1975a, Holstein and Roosen-Runge 1981, Sato and Oura 1985). The neck differs clearly from both the head and the tail in certain morphological features of the plasmalemma, a sharp demarcation of its upper limit by the posterior ring, and lack of continuity between the segmental columns and the outer dense fibres of the tail (Figs. 57 and 63) (Kaczmarski 1978).
KeywordsBasal Plate Basal Body Sperm Head Contractile Element Intramembranous Particle
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