Microscopic Anatomy of the Reproductive Apparatus of Male Neoechinorhynchus cylindratus (Acanthocephala)

Abstract

Neoechinorhynchus cylindratus males were collected from largemouth bass, Micropterus salmonides. Microscopic anatomy of the reproductive apparatus of N. cylindratus was determined by reconstruction from serial sections. A well developed syncytial cement gland emptied into a large cement reservoir from the posterior terminus of which 2 large ducts proceeded to the penis where they fused with the vas deferens to form the ejaculatory duct. The vas efferens from each testis joined to form the vas deferens at a level above Saefftigen's pouch but below the middle of the cement gland reservoir. A large seminal vesicle results from the union of the vasa efferentia. Major components of the reproductive system are illustrated from a longitudinal perspective supplemented with cross section diagrams of key areas. The taxonomic description of most species of Acanthocephala is typically based on whole mount studies. In this sense the anatomy of the reproductive system has probably been outlined. However, more detailed descriptions based on serial sections and reconstruction of components are much less common. Bieler (1913) reported on the microanatomy of 7 male reproductive apparatuses. Included in his analysis was an ex- amination of Neoechinorhynchus rutili and Neoechinorhynchus agilis. The latter has been considered a synonym of Neoechinorhynchus cy-