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The evolution of the eye in trilobites
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The schizochroal eye is shown to have had an internal muscular system, and may have been an organ for night vision, and an analysis is presented of its growth and form, different systems of lens-packing, and visual ranges.Abstract:
Clarkson, E .N.K.19 7 5 0 7 1 5 : The evolution of the eye in trilobites. Fossils and Strata, No. 4, pp . 7-3 1 , Oslo. ISSN 0300-949 1 . ISBN 8 2-00-04963-9. The earliest trilobites have fully differentiated compound eyes, and the subsequent evolution of the eye seems to have been controlled by only three factors: ( 1 ) Changes in proportion, surface curvature, etc ., through differential relative growth. ( 2 ) Paedomorphosis, which was probably the main factor in the origin of the schizochroal eye. (3 ) Incorporation of cuticular sensillae into discrete sensory zones peripheral to the eye. Cam brian eyes are rarely preserved due to the functional ocular suture. In post Cambrian trilobites, the visual surface is normally intact, and an analysis is presented of its growth and form (controlled by a logarithmic spiral genera tive zone ), different systems of lens-packing, and visual ranges. The schizochroal eye is shown to have had an internal muscular system, and may have been an organ for night vision.read more
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References
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Movements of the Retinae of Jumping Spiders (Salticidae: Dendryphantinae) in Response to Visual Stimuli
TL;DR: Jumping spiders distinguish other jumping spiders from potential prey by the geometry of their legs, and it is suggested that scanning is a pattern-recognition procedure in which the torsional movements are concerned with the spatial alignment of line or edge detectors, and the horizontal component with providing relative motion between these detectors and the stationary stimulus.