VII.—Experiments on the Respiratory Mechanism of the Shore Crab (Carcinus mænas)

Abstract

(a) The direction of the respiratory current is postero-anterior, whether the crab is above the sand or buried in it.(b) Reversal of this direction also occurs and is more frequent when the animal is buried or when a strong ink suspension is used during an experiment.(c) The sub-branchial cleft may be divided into four separate spaces which are in direct communication with gaps between certain gill origins, the whole constituting the sub-branchial inlets.(d) The direction of these inlets varies from postero-anterior to almost latero-medial.(e) They determine the direction of the inhaled currents within the branchial chambers.(f) The relation between the position of the gills and these inlets allows for a convenient and maximal flow.