Evidence of additional functions of the pericardial sacs in the bronchial ventilation in the grapsid crab Grapsus tenuicrustatus

الملخص EN

The pericardial sacs play an important role in branchial ventila-tion mechanisms in the semi-terrestrial grapsid crabs Grapsus tenuicrus-tatus.

The pressure change in these sacs leads to open or close the posterior branchial apertures.

Air flow inside the branchial chamb؛؛r causes pressure changes in the pericardial sac which enable the crab to absorb water from damp substratum.

Examination of sca^ognathite beat patterns indicated a number of distinct ventilation strategies, depending on whether the crabs were emersed or were immersed in sea water.

In former case, the pattern employed depends on the crabs activity state.

The volume of ؛،ir ventilated by rested crabs was determined.