Sensory receptors in the head of Stenostomum leucops. II. Localization of catecholaminergic histofluorescence-ultrastructure of surface receptors.

The ultrastructure of three types of sense receptors in the anterior end of Stenostomum leucops is described. Type I is characterized by abundant branching microvilli and ciliary rootlets but a lack of cilia. Type II possesses a short cilium with aberrant axonema. Type III has a cilium protruding from an invagination, a long rootlet and a collar of microvilli. The glyoxylic-acid-induced fluorescence method reveals catecholaminergic (CA) fluorescence in surface cells of the anterior end. The relationship between the CA fluorescence and the localization of the sense receptors is discussed.