Dr. Murai Éva szerk.: Parasitologia Hungarica 20. (Budapest, 1987)

Terminal genitalium The genital pore of amphistomes is situated on a more or less developed but distinct elevation. It is surrounded by fold(s) in subsequent concentric row(s) which enclose shallow cavities. These folds and cavities, seen on median sagittal section (in this plane they are called papilla and atrium, respectively) constitute the fundamental elements of the structure of this area. The folds and the wall of this area are furnished with different types of muscular elements whose position, arrangement and their relative constancy have been proved to be of important diagnostic value. This area was disclosed for the first time by NÄSMARK (1937) from the diagnostic point of view designating and characterizing parts of this terminal structure and piroved to be the basis for further examinations. His description, however, was incomplete in certain details, and was not free of confusions. These incompletions were rightly solved by EDUARDO (1982), who named all parts of this organ and established the name terminal genitalium for the whole terminal structure of the genital system. However, the terminal genitalium is used in this paper in a wider sense, the cirrus pouch, when it is present, is taken into consideration (Fig. 17). Schematic representation of the terminal genitalium without cirrus pouch and the terminology were.adopted from NÄSMARK (1937) and EDUARDO (1982) (Fig. 18). Fifty-eight different types of terminal genitalium are known presently. They can be divided into three groups: 1) terminal genitalium with cirrus pouch, 2) terminal genitalium with hermaphroditic pouch and 3) terminal genitalium without cirrus pouch and hermaphroditic pouch. The cirrus pouch is a smaller or larger sac with, in general, strongly developed muscular wall. It embraces the distal part of male genital duct (vesicula seminalis interna and pars prostatica). This organ is characteristic for many amphistomes which are mainly parasitic in lower vertebrates. In hermaphroditic pouch, the distal parts of male and female genital duct are found jointly in a cirrus pouch. It is covered with more or less developed muscle fibres. This is characteristic for some species of amphistomes of mammalian hosts. The group of terminal genitalium having neither cirrus pouch nor hermaphroditic pouch can be divided into two subgroups: 1) terminal genitalium with tegumental papillae, 2) terminal genitalium without tegumental papillae. Types of terminal genitalia with cirrus pouch This group includes five known types (Gastrodiscus Sey, 1975; Nematophila Sey, 1973; Scleroporum Sey, 1983; Spinolosum Sey, 1983; Stichorchis Sey, 1975) and three new ones described below. 1. Cladorchis type (Fig. 19) Whole terminal genitalium characterized by forming well developed genital sucker. Genital papilla usually slender; genital sphincter present, slightly or well-developed. Cirrus pouch equal with the diameter of terminal genitalium. Radial fibres evenly and strongly developed. (Valid for Cladorchis spp., Taxorchis schistocotyle, Stichorchis gigantheus.) 2. Dadayius type (Fig. 20) Genital pore surrounded by poorly developed sucker, well marked off from neighbouring parenchyma. Genital papilla clumsy, strongly developed, circular musculature entirely absent. Cirrus pouch small, its musculature poorly developed. Radial fibres moderately developed. (Valid for Dadayius marenzelleri.) I 3. Walteri type (Fig. 21) The whole terminal structure constitutes a well-developed genital sucker, clearly separated from the parenchyma. Strongly developed circular muscle units on the rim of the genital pa-