UNUSUAL SPERMATOZOAN FORMATIONS IN THE EPIDIDYMIS OF THE FLYING SQUIRREL (GLAUCOMYS VOLANS)

In the upper caput epididymidis of Glaucomys volans, where epithelial cells have a high concentration of RNA in their apical cyto¬ plasm, spermatozoa form long cylindrical bodies. Spermatozoan tails, adhering together, fill the interior of the cylinder. Their heads, with closely attached cytoplasmic droplets, are regularly arranged on the periphery of the cylinder with acrosomes facing the epididymal epithe¬ lium. In subsequent segments of the epididymis, the cylindrical bodies become more compact and the sperm heads are drawn together in rouleaux. In the lower caput epididymidis, cylindrical bodies fragment and masses of individual spermatozoa or spermatozoa grouped in rouleaux fill the lumina of the duct. It is suggested that in the flying squirrel the maturation of spermatozoa is accompanied by changes in their cohesive properties.