Summary
The lateral rudimentary eye of Limulus polyphemus, the horseshoe crab, is located beneath the posterior border of the compound eye. It consists of a bipartite mass of guanophores and about 100 associated photoreceptor cells. These neurons, up to 150 μ in diameter, have standard attributes of arthropod retinula cells and send large, uninterrupted axons to the brain. Their cytoplasm contains conspicuous clumps of residual bodies and variable, but usually extensive, masses of glycogen and glycoprotein. Hence, these neurons are not neurosecretory in the strict sense, notwithstanding axonal transport of glycogen masses toward the brain. Efferent axons to the rudimentary eye terminate in synaptoid fashion on the axon hillock of sensory cells. Since the rudimentary eye does not transmit impulses to the brain, but is photosensitive, its function may reside in a metabolic responsiveness to long-term changes in illumination.
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Bern, H. A., Hagadorn, I. R.: Neurosecretion. In: Structure and function in the nervous system of invertebrates (T. H. Bullock and G. A. Horridge), p. 353–428. San Francisco: W. H. Freeman & Co. 1965.
Brammer, J. D., White, R. H.: Vitamin A deficiency: Effect on mosquito eye ultrastructure. Science 163, 821–823 (1969).
Brown, J. E., Murray, J. R., Smith, T. G.: Photo-electric potentials from photoreceptor cells in ventral eye of Limulus. Science 158, 665–666 (1967).
Clark, A. W., Millecchia, R., Mauro, A.: The ventral photoreceptor cells of Limulus. I. The micro-anatomy. J. gen. Physiol. 54, 289–309 (1969).
Demoll, R.: Die Augen von Limulus. Zool. J. 38, 443–464 (1914).
Eakin, R. M., Brandenburger, J. L.: Differentiation in the eye of a pulmonate snail, Helix aspersa. J. Ultrastruct. Res. 18, 391–421 (1967).
—: Localization of vitamin A in the eye of a pulmonate snail. Proc. nat. Acad. Sci. (Wash.) 60, 140–145 (1968).
—, Westfall, J. A.: Fine structure of the eye of peripatus (Onychophora). Z. Zellforsch. 68, 278–300 (1965).
Eguchi, E., Waterman, T. H.: Fine structure patterns in crustacean rhabdoms. In: The functional organization of the compound eye (C. G. Bernhard, ed.), p. 105–124. Oxford: Pergamon Press 1966.
—: Changes in retinal fine structure induced in the crab Libinia by light and dark adaptation. Z. Zellforsch. 75, 209–229 (1967).
—: Cellular basis for polarized light perception in the spider crab, Libinia. Z. Zellforsch. 84, 87–101 (1968).
Fahrenbach, W. H.: The morphology of the eyes of Limulus. I. Cornea and epidermis of the compound eye. Z. Zellforsch. 87, 278–291 (1968).
—: The morphology of the eyes of Limulus. II. Ommatidia of the compound eye. Z. Zellforsch. 93, 451–483 (1969).
Goldsmith, T. H.: Fine structure of the retinulae in the compound eye of the honey-bee. J. Cell Biol. 14, 489–494 (1962).
Kleinholz, L. H.: Purines and pteridines from the reflecting pigment of the arthropod retina. Biol. Bull. 116, 125–135 (1959).
Millecchia, R., Bradbury, J., Mauro, A.: Simple photoreceptors of Limulus polyphemus. Science 154, 1199–1201 (1966).
—, Mauro, A.: The ventral photoreceptor cells of Limulus. II. The basic photoresponse. J. gen. Physiol. 54, 310–330 (1969a).
—: The ventral photoreceptor cells of Limulus. III. A voltage-clamp study. J. gen. Physiol. 54, 331–351 (1969b).
Nunnemacher, R. F., Davis, P. P.: The fine structure of the Limulus optic nerve. J. Morph. 125, 61–70 (1968).
Pannesi, P. A.: Anatomical studies on the optic nerve of Limulus polyphemus. Thesis. Clark University, Worcester, Massachusetts (1964).
Patten, W., Redenbaugh, W. A.: Studies on Limulus. II. The nervous system of Limulus polyphemus, with observations upon the general anatomy. J. Morph. 16, 91–200 (1900).
Perrelet, A., Baumann, F.: Evidence for extracellular space in the rhabdome of the honeybee drone eye. J. Cell Biol. 40, 825–829 (1969).
Rutherford, D. J., Horridge, G. A.: The rhabdome of the lobster eye. Quart. J. micr. Sci. 106, 119–130 (1965).
Scharrer, B.: Neurosecretion. XIV. Ultrastructural study of sites of release of neurosecretory material in blattarian insects. Z. Zellforsch. 89, 1–16 (1968).
Smith, T. G., Stell, W. K., Brown, J. E.: Conductance changes associated with receptor potentials in Limulus photoreceptors. Science 162, 454–455 (1968).
Wachmann, E.: Multivesikuläre und andere Einschlußkörper in den Retinulazellen der Sumpfgrille Pteronemobius heydeni (Fischer). Z. Zellforsch. 99, 263–276 (1969).
Waterman, T. H., Enami, M.: Neurosecretion in the lateral rudimentary eye of Tachypleus, a xiphosuran. Pubbl. Staz. zool. Napoli 24 (Suppl.), 81–82 (1954).
—, Horch, K. W.: Mechanism of polarized light perception. Science 154, 467–475 (1966).
Yamamoto, T., Tasaki, K., Sugawara, Y., Tonosaki, A.: Fine structure of the octopus retina. J. Cell Biol. 25, 345–359 (1965).
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This study constitutes publication No. 430 from the Oregon Regional Primate Research Center, supported by Grants FR00163 and EY00392 from the National Institutes of Health and by a Bop Hope Grant-in-Aid from Fight-for-Sight, Inc.
The author wishes to thank Mrs. Audrey Griffin for patient and excellent technical assistance.
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Fahrenbach, W.H. The morphology of the Limulus visual system. Z. Zellforsch. 105, 303–316 (1970). https://doi.org/10.1007/BF00335458
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DOI: https://doi.org/10.1007/BF00335458