ACTIVITY AND PHYSIOLOGICAL SIGNIFICANCE OF THE PLEOPODS IN THE RESPIRATION OFCALLIANASSA CALIFORNIENSIS(DANA) (CRUSTACEA: THALASSINIDEA)

Abstract

1. The pleopods of C. californiensis, a potential site for extrabranchial oxygen exchange, do not contribute significantly to oxygen consumption. 2. C. californiensis has a gill surface area of 4.13 ± 0.72 cm²/g wet body weight, the lowest value yet reported for a totally aquatic crustacean. 3. C. californiensis, when placed in simulated burrow conditions, regulates the PO₂ very loosely in its immediate microhabitat, using its pleopods. 4. Field studies of pH and PO₂ values in burrows of C. californiensis indicate that animal movement may play a large part in water exchange between the surface and burrow. 5. Activity studies suggest that oxygen is not critical to C. californiensis on a short term basis. Perception of oxygen after long deprivation may signal the possibility of renewed feeding and activity at the surface of its burrow.