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Ultrastructure of the flame bulbs and protonephridial capillaries of Prorhynchus (Lecithoepitheliata, Prorhynchidae, Turbellaria)
Author(s) -
ROHDE KLAUS,
WATSON NIKKI
Publication year - 1991
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/j.1463-6409.1991.tb00277.x
Subject(s) - anatomy , ultrastructure , biology , rib cage , transverse plane , biophysics
The flame bulb of Prorhynchus is formed by a single cell. Its nucleus is not located in the cytoplasm at the base of the flame. Cilia of the flame have cross‐striated hollow ciliary rootlets converging towards their tips. The maximum number of cilia counted was 13. The weir consists of a single row of longitudinal ribs that contain longitudinal filaments and possess regularly arranged protrusions along their surface appearing as transverse bands in horizontal section. A ‘membrane’ of extracellular material extends between the ribs. and loose material fills the places between the ribs, with a denser layer midway between adjacent ribs. Distally, the ribs fuse to form a continuous tube without a junction. Small protonephridial capillaries lack junctions, larger ducts have lateral flames and patches of long microvilli. Large excretory ducts open into a ciliated and lamellated cavity which is connected by a narrow canal to the excretory pore. The terminal part of the canal close to the pore possesses many cilia and microvilli. Phylogenetic implications of the findings are discussed.