Ultrastructure of the Feeding Apparatus of Pratylenchus penetrans

The feeding apparatus of Pratylenchus penetrans (Cobb) Chitwood and Oteifa was studied by means of the electron microscope. The stomatostylet is composed of tooth, shaft, and basal knobs. The tooth and shaft are closely interlocked. The tooth forms the outer covering and the inner lining of the anterior half of the stylet, whereas the shaft extends from the basal knobs to the level of the stylet opening. It is proposed that the shaft and knobs are living tissues, whereas the tooth is the product of sclerotized secretion. Stylet protractor muscles are attached to the basal knobs, and they become forked and split into 10 bundles as they extend anteriorly. Two types of secretory granules are observed in the dorsal esophageal gland, and they are different from those produced in the subventraI glands.