Morphology of urogenital system in female Echinopardalis atrata (Acanthocephala).

Four major areas of the urogenital system of Echinopardalis atrata are examined: (1) capsular protonephridial system, (2) uterine bell complex, (3) uterus, (4) vagina. Photomicrographs of cross sections from wax preparations depict morphological changes along the length of this system. Diagrammatic illustrations show relationships between excretory ducts and oviducts in the uterine bell complex. Relative positions of dorsal and ventral ligament accessory cells, median wall cells, and sheathing syncytium are also shown in this complex. The common oviduct and excretory canal join to form a ciliated urogenital canal that empties into the lumen of the uterus along the latter's anterior mid-dorsal surface. The excretory bladder is located on the inside mid-dorsal surface of the bell wall and is serviced by 2 nephridial canals--1 from each of 2 capsular protonephridia. The vagina affixes the posterior terminus of the uterus to the tegument and consists of an internal and external sphincter surrounding a hypodermal lining.