52 NERVE COMPONENTS OF BONY FISHES. 



(and terminal bud) fibres, which appear to be quite dis- 

 tinct from each other functionally and may be so anatomi- 

 cally, though we cannot as yet effect their analysis. The 

 pre-auditory portion of the fasciculus communis here, as 

 in the Amphibia, is composed mainly, though probably 

 not wholly, of fibres of the second of the classes enumer- 

 ated above, and it was these fibres which Strong had 

 primarily in mind in proposing the term " fasciculus com- 

 munis system." In the tract as a whole, however, he 

 recognized both types of fibres and also the motor com- 

 ponent ('95, p. 182). 



Now the fact that these kinds of fibres are developed in 

 varying degrees in different animals and the fact that 

 more or less of their terminal nuclei have sometimes been 

 included with them under the term fasciculus communis 

 have already occasioned considerable ambiguity as to what 

 is meant by this term and the matter of definition be- 

 comes important. I repeat, therefore, that under the 

 term communis system. I include the sensory cranial nerves 

 supplying the visceral surfaces, taste buds and terminal 

 buds, their ganglia, root fibres, peripheral end-organs and 

 terminal nuclei in the medulla oblongata. The term 

 fasciculus communis I shall use in its original sense as a 

 tract of fibres running from the seventh nerve caudad in 

 the oblongata and receiving in different animals varying 

 proportions of the root fibres of the communis system. 

 Other root fibres of that system may pass to their terminal 

 nuclei directly without entering the fasciculus communis. 

 The fasciculus communis may contain in some part of its 

 course viscero-motor fibres ; but, if so, such fibres are not 

 regarded as belonging to the communis system, which is 

 wholly sensory. 



