Morphology of the cysticercoid of Hymenolepis erinacei (Gmelin, 1789).

The morphology of the cysticercoid of H. erinacei has been studied for the first time by histological methods. The cysticercoid consists of a tailed cyst enclosing the neck and scolex of the cestode. The outer limiting layer surrounds the surface of the cyst, neck and scolex. The tegument of the cyst is characterized by circular and longitudinal layers of fine connective tissue fibres. The tegument of the proximal part of neck and scolex is characterized by microtriches. The basement layer is of fibrous character. The subtegument of the cyst, neck and scolex is formed by outer circular and longitudinal muscle and connective tissue layers and a layer of pyriform cells. The subtegument of the cyst is further formed by an inner longitudinal muscle and connective tissue layer with distinctly prevailing connective tissue fibres forming a lamellar structure. Under the subtegument of the cyst is an inner zone consisting of oval nuclei and cytoplasmic processes, without distinct cellular borders. The parenchyma is situated under the subtegument of the neck and scolex. The inner edge of the cyst and neck is bordered by the inner limiting layer.