Afferent and efferent myelinated fibres in branches of the avian vagus

The numbers of afferent and efferent myelinated fibres in the branches of the vagus nerve in the domestic fowl were studied. The vago-glossopharyngeal anastomosis contained large fibres (up to 14 micrometer), the majority of which were efferent. The right recurrent nerve contained more fibres than the left one; in the right recurrent nerve about one third of the myelinated fibres were afferent. Almost all the myelinated fibres in the right cranial cardiac nerve were afferent. About half of those in the pulmono-oesophageal nerve and in the thoracic vagus were afferent.