That have developed a membrane

A mechanical, thin, flat flexible part that can deform or vibrate when excited by an external force. / A flexible or semiflexible covering or waterproofing whose primary function is to exclude water.

(anatomy, zoology) Having the qualities of, or pertaining to, a membrane. / (medicine) Accompanying the formation of a usually abnormal membrane or membranous layer.

plural of membrane / (medicine, informal, specifically) The amniotic sac.

Having a (specified type of) membrane.

Alternative form of membranous

Of or pertaining to a membrane.

In a membranous manner.

Having the character of a membrane.

Relating to a membrane