Effects of induced aestivation in Protopterus annectens: a histomorphological study.

The aim of this research was to induce, at will in the laboratory, aestivation of the Dipnoan Protopterus annectens, in order to compare the structure of organs in lungfish adapted to aquatic or aestivating conditions. The animals were placed in a glass tank containing warm water, and the bottom of the tank was filled with clay and sand. To start aestivation the water was allowed to slowly evaporate; as soon as the fish was in a dry environment, it began to excavate a hole in the mud and to burrow into it.