Complemental /(?)/

Com·ple·men·tal

Complemental

a.
  1. Supplying, or tending to supply, a deficiency; fully completing.
  2. Complimentary; courteous. [Obs.]

Phrases & Compounds
Complemental air
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
peculiar small males living parasitically on the ordinary hermaphrodite individuals of certain barnacles.