membranous

/ˈmɛmbrənəs/
adjective
  1. Relating to, consisting of, or resembling a membrane; thin, flexible, and skin-like.
    • The membranous tissue inside the egg protects the developing chick.
    • Some jellyfish have a membranous bell that pulses to move through water.
    • The plant's membranous leaves are almost transparent.