Temereva E.N.1, Malakhov V.V. 2004. [Distinctive features of the microscopical anatomy and ultrastructure of the metanephridia Phoronopsis harmeri Pixell, 1912 (Phoronida, Lophophorata)] // Invertebrate Zoology. Vol.1. No.1: 93–103 [in Russian, with English summary].

Department of Invertebrate Zoology, Biology Faculty, Moscow State University, Moscow 119899, Russia. 1 E-mail: temereva@mail.ru

ABSTRACT: The microscopical anatomy of metanephridia Phoronopsis harmeri (Phoro­nida) was described. Sexual dimorphism in the structure of the distal parts of metanephridia was found and described. Female metanephridium has two ciliated funnels, whereas male metanephridium has only one. Description of the fine structure of all metanephridial parts (funnel, ascending and descending branches) was given. Epithelium of the nephrostome consists of myoepithelial cells with myofibrils in the apical parts of the cells. Miofibrils are also found in the apical and basal parts of cells of the ascending metanephridial branch. The differences between the fine structure of the ascending and descending metanephridial branches were found and described. Epithelial cells of the descending branch contain many cisterns of the rough and smooth endoplasmic reticulum, but these cells practically lack mitochondria. In contrast, epithelial cells of the ascending branch have many mitochondria and very few cisterns of the endoplasmic reticulum. These differences were discussed in the view of different functions of ascending and descending metanephridial parts.

KEY WORDS: Phoronida, ultrastructure, metanephridium.

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