Membranous rhymes with:
asynchronous, patroness, uranus, androgynous, asynchronous, bituminous, brazenness, chitinous, deaconess, exogenous, gelatinous, givenness, gluttonous, homogenous, indigenous, larcenous, luminous, monotonous, mountainous, mutinous, nitrogenous, nonpoisonous, oleaginous, ominous, outspokenness, patroness, poisonous, polygynous, ravenous, ruinous, tetanus, titinus, uranus, villainous, voluminous
Membranous sounds like:
mainframes, maneuvering, maneuverings, membranes