VOLTZOW, J.; Univ. of Scranton: Principally Continuous Flow in Gastropod Mantle Cavities

The flow of water through a gastropod mantle cavity follows the same basic principle of continuity that describes flow through a series of pipes. Regions with the largest total cross-sectional areas should have the slowest flow rates and regions with the smallest cross-sectional areas should have the highest rates. Measurements of the dimensions of the paths through which water flows in the marine gastropods Diodora aspera and Fasciolaria hunteria illustrate that, as expected, the largest total cross-sectional area is located at the many parallel channels between gill lamellae and that the smallest cross-sectional areas lie at the incurrent and excurrent windows, where the water enters and exits the shell. Measurements of flow rates at the incurrent and excurrent windows indicate that flow through the mantle cavities in these animals follows the principle of continuity. This, in turn, permits the prediction of flow rates along the length of the path of flow.