ISSN:
1432-0878
Keywords:
Eye
;
Arthropods
;
Neurosecretion
;
Microscopy, Electron
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00335458
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