The central projections of the glossopharyngeal and vagus ganglia in the mallard, Anas platyrhynchos L.

The central projections of the glossopharyngeal and vagus nerves in the mallard have been studied with the Fink-Heimer I method and are compared to those of the trigeminal and facial nerves. The N. vagus projects ipsilaterally and contralaterally upon the central nuclei of the solitary complex, except the most rostral part of it, upon the n. sulcalis dorsalis, the parasolitary nuclei and the n. commissuralis. The glossopharyngeal nerve contributes to the rostral pole of the n. centralis anterior and to the n. ventrolateralis anterior of the solitary complex, but it has also terminal fields in a cellgroup sIX of the principal sensory trigeminal nucleus, in a small cellgroup sIXd on the dorsum of the descending trigeminal tract, in the n. interpolaris of this tract and in nuclei of the cuneate complex. There is hardly any overlap of the respective terminal fields. The convergence of projections from N VII and N IX can be connected with the presence of tastebuds in upper and lower bill and in the soft palate. The converging projections from N V and N IX in "trigeminal" nuclei may reflect the functional coherence of the mechanoreceptors in bill and tongue. It is suggested that these nuclei play a role in the feeding behavior.