Electron microscopic investigation of the formation of spermatophores of Armadillidium vulgare.

An ultrastructural investigation of the formation and morphology of spermatophores of the isopod, Armadillidium vulgare, has been conducted. Armadillidium spermatozoa are organized into bundles ensheathed by a specialized structure that functions as a spermatophore. The spermatophore is an extracellular investment consisting of two components: (1) a cone-shaped assembly of longitudinally aligned, 400 to 450 A diameter extracellular tubules, extending from the area rostral to sperm acrosomes to the region of sperm nuclei; and (2) matrix material, which surrounds spermatozoa for the entire length of the bundle. Morphological evidence suggests the participation of the rough endoplasmic reticulum and Golgi apparatus of testicular follicle cells in the production of tubular and matrix components of the spermatophore. Although the organization of spermatophores is similar throughout the male reproductive tract, the morphology of the matrix material appears to change at lower regions of the tract.