01427nas a2200121   4500008004100000245011000041210006900151300001000220490000800230520099900238100001601237856005201253       1982                        eng d00aUltrastructure of copulatory organs in Turbellaria: 1. Macrostomum sp. and Microstomum sp. (Macrostomida)0 aUltrastructure of copulatory organs in Turbellaria 1 Macrostomum  a39-600 v1013 aThe copulatory organs in Macrostomum sp. and Microstomum sp. contain simple tubular stylets which are intracellular specializations. The stylet in Macrostomum sp. is produced in a syncytium covering part of the prostatic vesicle. The proximal region of the stylet surrounds the vesicle which contains 6 prostatic gland ducts and 6 accessory (sensory) cells containing ciliary rootlets. The stylet in Microstomum sp. is produced in an extension of a syncytium which lines the combined seminal-prostatic vesicle. The stylet is connected to the combined vesicle by a narrow bridge of matrix syncytium through which sperm, prostatic gland products and sensory cilia pass from the vesicle to the stylet lumen. In both species the matrix syncytium can be interpreted as a specialized terminal end of the male canal epithelium. Stylets of Turbellaria and other lower Metazoa are discussed in regards to structure (1 or several pieces) and location (in separate cells, in a syncytium or extracellular).1 aDoe, D., A.  uhttps://macrostomorpha.myspecies.info/node/469401679nas a2200121   4500008004100000245011000041210006900151300001200220490000800232520124900240100001601489856005201505       1986                        eng d00aUltrastructure of the copulatory stylet and accessory spines in Haplopharynx quadristimulus (Turbellaria)0 aUltrastructure of the copulatory stylet and accessory spines in   a157-1630 v1323 aThe copulatory organ of Haplopharynx quadristimulus Ax, 1971 (Carolina form, Rieger, 1977) consists of a proximal prostatic vesicle and a distal stylet apparatus comprising a central tubular stylet and four to five peripheral accessory spines . By electron microscopy it could be seen that the stylet and spines were intracellular specializations . The copulatory organ can be interpreted as a specialization of an epithelial canal extending from the testes to the body wall . In the complex stylet apparatus, the epithelium was differentiated into six cell types. The stylet, which was formed in a matrix syncytium next to the prostatic vesicle, extended into the lumen of the stylet canal . The interior of the stylet apparatus contained one group of cells that had thick ciliary rootlets and another that had rootlet-like ribbons . The cells that contain the rootlets enveloped bundles of longitudinally arranged muscles. The accessory spines were formed in cells which lay peripheral to the muscle bundles . The spines, stylet, rootlet-like ribbons, and rootlets had similar patterns of periodic cross striations . The similarity in striation patterns suggests that the accessory spines and stylet are composed of modified ciliary rootlets.1 aDoe, D., A.  uhttps://macrostomorpha.myspecies.info/node/469301830nas a2200121   4500008004100000245014200041210006900183300001200252490000800264520136800272100001601640856005201656       1986                        eng d00aUltrastructure of the copulatory organ of Haplopharynx quadristimulus and its phylogenetic significance (Plathelminthes, Haplopharyngida)0 aUltrastructure of the copulatory organ of Haplopharynx quadristi  a163-1730 v1063 aThe male reproductive system in Haplopharynx quadristimulus consists of paired testes, sperm ducts, seminal vesicles, seminal ducts, a copulatory organ containing prostatic vesicle and stylet apparatus, and the male canal. By electron microscopy all components appeared to be regional specializations of a canal extending from the testes to the body wall and lined by a multiciliated epithelium. The epithelium of the stylet apparatus contained six different cell types. One cell type (matrix syncytium) formed the stylet and the other five were located distal to the stylet/ prostatic-vesicle junction along the male system epithelium. Each cell type was attached to the supporting intercellular matrix at a different level along the stylet apparatus. All cell types extended to the distal end of the stylet apparatus regardless of where they originated along its length. The cells in the apparatus lacked cilia, but one of the cell types contained rootlets. Modified rootlets or rootlet derivatives were possibly present in another cell type in the form of rootlet-like ribbons. The findings support the monophyly of the Macrostomida Haplopharyngida (by common occurrence of a matrix syncytium) and at the same time suggest their separation as two distinct taxa (by differences in the structure of the prostatic vesicle and other parts of the stylet apparatus).1 aDoe, D., A.  uhttps://macrostomorpha.myspecies.info/node/3754