ISSN:
1615-6102
Keywords:
Chiasma opticum
;
Hydrozetes
;
Lamellated body
;
Oribatida
;
Photoneuron
;
Secondary eye
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The lenticulus ofHydrozetes lemnae represents an eye composed of a single cuticular cornea underlain by flat extensions of epidermal cells, two pigment cells, and a pair of lamellated bodies. The latter consist of about 100 vertically arranged lamellae which are orientated longitudinally in the animal. The lamellated bodies are accompanied by glia cells. Two large fat body cells separate the paired components medially. Each lamellated body is connected to a perikaryon located in the brain. It is evident that these components are parts of photoneurons of the central nervous system. Their vertically directed extensions are dendritic branches, terminating under the cornea as lamellated bodies. It is assumed that these are the photosensitive parts of the two photoneurons which serve as receptor cells. The axon of each cell runs transversely through the brain and terminates in a small distinct optic neuropile close to the opposite perikaryon. Thus the resulting chiasma opticum comprises two axons only. The extraordinary composition of this eye corroborates the assumption that it is a secondary light sense organ.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01405919
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