This membrane along with hypoblast forms the primary yolk sac.

Sometimes a membrane forms across the throat requiring a tracheostomy to prevent suffocation.

With a worrisome sucking sound, the membrane switched functions and formed gloves around my hands.

A membrane can form across the throat, requiring a tracheostomy to prevent suffocation.

This membrane can form a basket or pouch to help catch and hold insects captured in flight.

Such membranes formed the top, bottom and two sides of a box in which the hamster was submerged in water.

The membrane has been known since as membrana Jacobi and forms the retina.

After the living tissue is crushed into suspension, various membranes form tiny closed bubbles.

Already the neck arteries had sealed themselves off and a protective membrane was forming.

A diphtheritic membrane may form in the trachea, causing obstruction.