Biradial Assymetry

Biradial symmetry is a combination of radial and bilateral symmetry, as in the Ctenophores. Here, the body components are arranged with similar parts on either side of a central axis, and each of the four sides of the body is identical to the opposite side but different from the adjacent side. This may represent a stage in the evolution of bilateral symmetry “from a presumably radially symmetrical ancestor.”

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