Ultrastructural changes in spermatozoa of the brush-tailed possum, Trichosurus vulpecula (Marsupialia), during epididymal transit

摘要: During epididymal transit, a fibre network and an array of vesicles develop in the posterior two-thirds midpiece sperm Brush-tailed possum, Trichosurus vulpecula. The is developed by time reach corpus epididymidis, composed evenly spaced, helically arranged fibres lying immediately beneath plasma membrane. angle these fibrous helices always counter to that underlying mitochondrial helix. Separating from mitochondria layer granular material which develops at same time, over length as network. A somewhat tenuous found between sheath membrane anterior principal piece all regions epididymis. cauda epididymidis. resemble pinocytotic vesicles; some appear invaginations membrane, are open medium surrounding spermatozoon narrow neck, while others entirely enclosed within spermatozoon, lie varying distances material.