Summary
Organs of presumed photoreceptor significance in Nephtys exhibit great simplicity. The pigmented eyes of Nephtys are embedded in the posterior region of the brain. Each consists of a pigment cup and two closely-associated sensory cells. The cells exhibit the characteristic features of rhabdomeric-type photoreceptor structures. The anterior or accessory eyes are identical to the pigmented eyes except that each may consist of only a single cell and that pigment cups are absent. A pair of “sensor sacs” is also present, embedded in the brain. Each consists of a single cell which has the appearance of possessing a large intracellular vesicle (the phaosome) into which project irregularly arranged microvilli. The limiting membrane is, in fact, continuous with the cell membrane. Evidence is presented of the secretion of material of unknown character into the vesicle.
Similar content being viewed by others
References
Barber, V. C., Evans, E. M., Land, M. F.: The fine structure of the eye of the mollusc Pecten maximus. Z. Zellforsch. 76, 295–312 (1967)
Bern, H. A.: On eyes that may not see and glands that may not secrete. Amer. Zool. 7, 815–821 (1967)
Boquet, M., Dhainaut-Courtois, N.: Etude infrastructurale de l'organ photorécepteur des Syllidae (Annélides, Polychètes). C. R. Acad. Sci. (Paris) 274, 1689–1692 (1972)
Bullock, T. H., Horridge, G. H.: Structure and function in the nervous systems of invertebrates. San Francisco: W. H. Freeman 1965
Clark, A. W.: The fine structure of the eye of the leech, Helobdella stagnalis. J. Cell Sci. 2, 341–348 (1967)
Clark, R. B.: The eyes and the photonegative behaviour of Nephtys (Annelida, Polychaeta). J. exp. Biol. 33, 461–477 (1956)
Clark, R. B.: The micromorphology of the supra-oesophageal ganglion of Nephtys. Zool. Jb. Abt. allg. Zool. u. Physiol. 68, 261–296 (1958)
Clark, R. B.: Secretory activity in the nervous system. In: Some contemporary studies in marine science (ed. H. Barnes), p. 129–154. London: Allen and Uwin 1966
Dhainaut-Courtois, N.: Sur la présence d'un organ photorécepteur dans le cerveau de Nereis pelagica L. (Annélide, Polychète). C. R. Acad. Sci. (Paris) 261, 1085–1088 (1965)
Dhainaut-Courtois, N.: Etude histologique et ultrastructurale des cellules nerveuses du ganglion cérébral de Nereis pelagica L. (Annélide, Polychète). Comparison entre les types cellules I–VI et ceux décrits antérieurement chez les Nereidae. gen. comp. Endocr. 11, 414–443 (1968)
Dorsett, D. A., Hyde, R.: The fine structure of the lens and photoreceptors of Nereis virens, Z. Zellforsch. 85, 243–255 (1968)
Eakin, R. M.: Lines of evolution of photoreceptors. In: General physiology of cell specialization (eds. D. Mazia and A. Tyler), p. 393–425. New York: McGraw-Hill 1963
Eakin, R. M., Westfall, J. A.: Further observations on the fine structure of some invertebrate eyes. Z. Zellforsch. 62, 310–332 (1964)
Fischer, A., Brokelmann, J.: Das Auge von Platynereis dumerilii. Z. Zellforsch. 71, 217–244 (1966)
Golding, D. W.: Studies in the comparative neuroendocrinology of polychaete reproduction. Gen. comp. Endocr., Suppl. 3, 580–590 (1972)
Golding, D. W.: Neuroendocrine phemonena in aphroditid and related polychaetes. I. The morphology and cytology of the infracerebral gland and cerebral neurosecretory system. Acta zool. (Stockh.) 54, 101–120 (1973)
Hauenschild, C.: L'influence de l'hormone du cerveau sur le développement postembryonaire de Platynereis dumerilii. Ann. Endocr. 25, 49–56 (1964)
Krasne, F. B., Lawrence, P. A.: Structure of the photoreceptors in the compound eyespots of Branchiomma vesiculosum. J. Cell Sci. 1, 239–249 (1966)
Morgan, E.: The responses of Nephtys (Polychaeta, Annelida) to changes in hydrostatic pressure. J. exp. Biol. 50, 1–13 (1969a)
Morgan, E.: The possible role of the supra-oesophageal ganglion in the responses of Nephtys (Polychaeta, Annelida) to changes in hydrostatic pressure. J. exp. Biol. 51, 171–179 (1969b)
Röhlicb, P., Aros, B., Virágh, S.: Fine structure of photoreceptor cells in the earthworm, Lumbricus terrestris. Z. Zellforsch. 104, 345–357 (1970)
White, R. H., Walther, J. B.: The leach photoreceptor cell: ultrastructure of clefts connecting the phaosome with extracellular space demonstrated by lanthanum deposition. Z. Zellforsch 95, 102–108 (1969)
Author information
Authors and Affiliations
Additional information
Supported in part by Grant 4610 from the Ministry of Higher Education, Iraq.
Supported by Research Grant B/SR 9636 from the Science Research Council, U.K.
Rights and permissions
About this article
Cite this article
Zahid, Z.R., Golding, D.W. Structure and ultrastructure of the central nervous system of the polychaete Nephtys, with special reference to photoreceptor elements. Cell Tissue Res. 149, 567–576 (1974). https://doi.org/10.1007/BF00223033
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00223033