Abstract
A MODEL consisting of a football bladder and rubber blocks, to illustrate how early forms of sea-urchins (of Cambrian age) may have behaved under tidal conditions, has been constructed by Dr. W. K. Spencer. The model opens and closes automatically under the influence of changes in hydrostatic pressure, acting upon the elastic body-walL
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Points from Foregoing Letters. Nature 136, 686 (1935). https://doi.org/10.1038/136686a0
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DOI: https://doi.org/10.1038/136686a0