Hydrodynamic sensitivity by cuticular organs in the rock lobsterPalinurus vulgar is.Morphological and physiological aspects

Abstract

The present work concerns previously undescribed external sense organs observed on the rock lobster Palinurus vulgaris L. Each sensilla is composed of a feather‐like extension inserted in a cuticular depression in the rim of which there is a knob, the significance of which is discussed. Two or three bipolar cells innervate each organ. These organs are present in great numbers broadly distributed on the dorsal and lateral parts of the exoskeleton and have been named, considering their physiological properties, “hydrodynamic receptors”; (HR). Various stimulations (micromanipulation, water current and vibration) have been applied to determine the different responses. Electrophysiological findings demonstrate their bidirectional sensitivity. The role of the different HR in behavioural activities of rock lobster is discussed. It is suggested that during escape they can contribute information to the animal of its o4wn displacement.