The cephalic sense organs of adult female Hammerschmidtiella diesingi (Nematoda: Oxyuroidea)

The ultrastructure of the cephalic sense organs of Hummerschmidtiella diesingi (Hammer‐Schmidt, 1838), a parasite of cockroaches, is described using scanning and transmission electron microscopy. The four cephalic papillae are apparently mechanoreceptors and terminate as flattened dendritic processes within the cuticle. The hypodermis and sheath cells associated with these are described. The amphids resemble those described for other nematodes and are thought to be chemosensory. Each contains six main dendritic processes within the amphidial canal. Double and single microtubules, of varying arrangement, are present within these processes but basal bodies have not been found. The association between the amphids, the amphidial sheath cells and the hypodermis is also described. The inner and outer labial papillary neurons terminate beneath the cuticle and do not innervate cuticular sense organs. The outer labial dendrites, however, do produce dendritic processes. Possible functions of these sense organs are discussed.