What does "complemental" mean?

Complemental: Complimentary; courteous. [Obs.] Shak. Complemental air (Physiol.), the air (averaging 100 cubic inches) which can be drawn into the lungs in addition to the tidal air, by the deepest possible inspiration. -- Complemental males (Zoöl.), peculiar small males living parasitically on the ordinary hermaphrodite individuals of certain barnacles.

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