Two newly described sensory systems in decapod crustacea : 1. The campaniform organ system. 2. The chemoreceptor hair system

Abstract

(1) Evidence is presented that the ''Funnel Canal Organs" described by Luther (1930) are not contact chemoreceptors. (2) Experiments are described which indicate that the Funnel Canal Organ is a mechanoreceptor which responds to strain applied to the cuticle. (3) Histological observations suggest that these sense organs are actually campaniform sensilla which occur both singly and in groups, to form compound sense organs. (4) The relationship between campaniform and chordotonal organs is discussed. (5) Further experiments show that a large variety of chemoreceptor hairs exits. Most are branched and there is a negative correlation between the surface area of the hair (degree of branching) and the amount of irrigation to which the hair is normally subject. (6) The view is expressed that the concert of contact chemoreception is of limited use when considering aquatic Crustacea. The Hair Plate Organs of the chelate pereiopods are suggested as the only chemoreceptor organs in aquatic Decapoda which fulfil a true contact role.