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acrania

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noun acra·nia \(ˈ)ā-ˈkrā-nē-ə\

Medical Definition of acrania

  1. :  congenital partial or total absence of the skull

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Acrania

noun plural acra·nia

Medical Definition of Acrania

  1. in some classifications :  a division of the phylum or subkingdom Chordata comprising the hemichordates, tunicates, and lancelets and including all the chordates without true heads and anterior brains—compare vertebrata

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