Abstract
IN this urchin, podia withdraw in response to sudden shading. When the aboral hemisphere was subjected to an illumination of 250 metre-candles from a tungsten filament lamp, according to the individual, a 3–20 per cent decrease in intensity proved a minimal stimulus. Most of the podia responded simultaneously when the light was relatively bright; but when dim, or when the shadow was faint, many fewer responded and then at different times.
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MILLOTT, N., YOSHIDA, M. Reactions to Shading in the Sea Urchin, Psammechinus miliaris (Gmelin). Nature 178, 1300 (1956). https://doi.org/10.1038/1781300a0
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DOI: https://doi.org/10.1038/1781300a0
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