The histochemistry and ultrastructure of the glandular vas deferens of Tubifex tubifex (Annelida: Oligochaeta)

The ultrastructure and histochemistry of the atrium, prostate gland and penis of Tubifex tubifex are described. The prostate gland, which forms a discrete structure alongside the atrium, consists of club-shaped gland cells with narrow cell processes that converge onto the junction with the atrium, Prostate perikarya contain abundant rough endoplasmic reticulum (rER) and active Golgi cisternae and function in the synthesis of secretion granules. Prostate cell processes, characterized by a peripheral band of microtubules linked to an electron lucent cisterna derived from the perikaryon rER, penetrate the atrium and ramify between the atrial epithelium and musculature. The atrial epithelium consists of interstitial ciliated cells and anucleate glandular clements packed with secretion granules. Prostate cell processes ultimately open into the bases of the atrial glandular elements which therefore constitute the expanded apices of prostate cells. The morphological differentiation of prostate atrial gland cells into distinct zones concerned with the production, translocation and storage of secretion granules is discussed in relation to sperm transmission. The presence of a conventional peritoneum surrounding the prostate gland indicates that the gland cells originate from the atrial epithelium. The prostate-atrial gland cells are of two types characterized by the ultrastructure and histochemistry of their secretion granules. Type I granules are uniformly electron dense and are composed of neutral mucopolysaccharide with vic glycol groups and basic protein containing tyrosine, tryptophan and cystine. Type I1 granules are heterogeneous and consist of electron dense subunits of basic protein within a microfibrillate matrix composed of carboxylated acid mucopolysaccharide. The possible function of prostatic secretion is discussed. The penis is composed of a simple tubular extension of the epithelial, muscular and peritoneal cells of the male duct-body wall junction and is enclosed within a double foldin the epidermis. The penis lumen is plugged by secretion derived from the prostate-atrial gland cells.