Abstract
The ultrastructure of the paired lateral ciliary pits in several endemic species of Geocentrophora from Lake Baikal and in one cosmopolitan species, G. baltica, has been compared and the possible functional significance is discussed. The pit is composed of two distinctive parts; the bottom of the pit is an extensive sensitive area, filled with uni-and biciliary sensory receptors with reduced rootlets and numerous neurotubules. The walls of the pit are formed by several large ‘dark cells’, characterized by a dark cytoplasm with numerous mitochondria, a large nucleus, intracellular canaliculi, basal infoldings of the cell membrane, glycogen granules and a varying number of cilia. A protruding, densely ciliated ridge occurs along the anterior wall of the pit. The cilia have a strengthened rootlet system and seem to provide a strong water current into the pit. Dark cell processes penetrate the basement membrane of the pit and come into the vicinity of large cells with a cytoplasm similar to that of the ‘dark cells’ of the pit. These large cells in their turn come close to the terminal parts of the protonephridial canals, containing a weir. Smaller protonephridial capillaries without a weir seem to open directly into the pit lumen. The morphological data obtained suggest that the ciliary pit in not only a sensory structure, but plays a part in osmoregulation and ion exchange as well.
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References
Böckerman I., M. Reuter & O. Timoshkin, 1994. Ultrastructural study of the central nervous system of endemic Geocentrophora (Prorhynchidae, Plathelminthes) from Lake Baikal. Acta Zool. (Stockholm) (in press).
Kepner W. A. & W. H. Taliaferro, 1916. Organs of special sense of Prorhynchus applanatus Kennel. J. Morphol. 27: 163–177.
Kikuchi, S., 1983. The fine structure of the gill epithelium of a freshwater flea Daphnia magna (Crustacea: Phyllopoda) and changes associated with acclimation to various salinities. Cell Tissue Res. 299: 253–268.
Mendez, A., J. L. Arias, D. Tolivia & M. Alvarez-Uria, 1984. Ultra-structure of gill epithelial cells of Diopatra neapolitana (Annelida, Polychaeta). Zoomorphology 104: 304–309.
Reisinger, E., 1968. Xenoprorhynchus - ein Modellfall fiir progressiven Funktionswechsel. Z. Zool. Syst. Evolutionsforsch. 6: 1–55.
Reuter, M., B. Joffe & I. Palmberg, 1993. Sensory receptors in the head of Stenostomum leucops. II. Localization of catecholaminergic histofluorescence - ultrastructure of surface receptors. Acta Biol. Hungarica 44: 125–131.
Rieger, R. M., S. Tyler, J. P. S. Smith III & G. E. Rieger, 1991. Platyhelminthes, Turbellaria. In F. W. Harrison & B. J. Bogitsh (eds) Microscopic Anatomy of Invertebrates, 3. Wiley-Liss. Inc, New York, Chichester, Brisbane, Toronto, Singapore: 7–140.
Timoshkin,O. A. 1991. Turbellaria Lecithoepitheliata: morphology, systematics, phylogeny. Hydrobiologia 227 (Dev. Hydrobiol. 69): 323–332.
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© 1995 Springer Science+Business Media Dordrecht
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Raikova, O.I., Reuter, M., Böckerman, I., Timoshkin, O.A. (1995). Ultrastructure of the ciliary pits in the Geocentrophora group (Platyhelminthes, Lecithoepitheliata). In: Cannon, L.R.G. (eds) Biology of Turbellaria and some Related Flatworms. Developments in Hydrobiology, vol 108. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-0045-8_29
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DOI: https://doi.org/10.1007/978-94-011-0045-8_29
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