naturalist are constantly adding to the number. The specific distinctions are for the most part based, not upon characters directly presented {747} by the living animal, but upon the form, size and arrangement of the little cups, or ãcalycles,ã secreted and inhabited by the little individual polypes which compose the compound organism. The variations, which are apparently infinite, of these conformations are easily seen to be a question of relative magnitudes, and are capable of complete expression, sometimes by very simple, sometimes
Table of Contents
CHAPTER XVII ON THE THEORY OF TRANSFORMATIONS, OR THE COMPARISON OF RELATED FORMS
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