124 NERVE COMPONENTS OF BONY FISHES, 



The viscero-motor fibres are of two types, coarse fibres 

 from the nucleus ambig'uus for the striated branchial 

 musculature and fine fibres of unknown origin for the 

 musculature (mainly unstriated) of the viscera. The 

 communis fibres all terminate in the lobus vagi. They 

 have three types of peripheral endings, viz. : (i) undiffer- 

 entiated termini in the general visceral and mucous sur- 

 faces and more highly specialized termini in (2) taste buds 

 and (3) terminal buds on the outer skin. The two latter 

 classes of fibres are more numerous in the more cephalic 

 branches of the complex, the former class in the more 

 caudal branches, some of which they compose exclusively 

 (intestinal and oesophageal rami). The general cutaneous 

 fibres terminate in the spinal V tract and are distributed 

 only to the outer skin by means of undifferentiated end- 

 ings. The acustico-lateral fibres terminate mainly, if not 

 wholly, in the tuberculum acusticum. They enter the 

 brain only through the lateralis root and distribute only to 

 organs of the lateral line. 



The general scheme for the branchial nerves in Menidia 

 may be expressed as follows : Each trimcus brancJiialis 

 arises from a special lobe of the general vagus ganglion 

 and gives off the following rami. 



I. — Pharyngeal rami, motor and sensory, supplying the 

 pharyngeal muscles, taste buds, pharyngeal teeth, glands 

 and mucous surfaces in general. They may arise from the 

 truncus branchialis or from either the pre- or post-trematic 

 ramus, or both, or from the ganglion directly. There is 

 no branchiomeric uniformity as regards either their num- 

 ber or size, though the main sensory pharyngeal ramus is 

 evidently typically associated with the pre-trematic ramus. 

 These sensory fibres increase in number and importance 

 as we pass caudad. They are reduced in the IX nerve. 



