The egg is commonly considered to be one of the most vulnerable stages of the life cycle, particularly in terrestrial amphibians whose eggs are laid in non-aquatic situations and yet lack a protective shell. In the terrestrial salamander, Plethodon cinereus, the eggs usually hang from the roof of a cavity inside or under logs, and are frequently in partial contact with the surrounding materials. Whether such an egg can absorb water may be of importance to its survival. Also of possible significance is the absorption of water from, or loss of it to, the body of the female, which curls around the eggs and remains with them throughout the developmental period. The ability of eggs of a terrestrial amphibian to absorb water has not been previously studied quantitatively. For this reason the following experiments were carried out.