Ultrastructure of the rhyncheal system of Trimacracanthus aetobatidis (Cestoda:Trypanorhyncha)

Abstract

The rhyncheal system of T. aetobatidis comprises the tentacle, tentacle sheath, tentacular bulb, retractor muscle and prebulbar organ. The tentacle is covered externally by an electron-dense lamina into which the hooks are inserted. Internally, a complex of fibrillar and vesicular layers is present with a few muscle fibres. The fibrillar sub-surface layers of the tentacle are continuous with the sheath, and the sheath persists as an outer coat to the bulb. The ultrastructure of the tentacle has homologies with the basal lamella of the scolex tegument and the two are probably continuous. The bulb is composed of vacuolated striated muscle fibres while the muscles of the retractor muscle and th..