Kappers, Tcleostean and Selachian Brain. 97 



cosa of the mouth between the hyoid and the mandibular arches, 

 where it reaches to the ventral median line of that region. Thus, 

 both in its peripheral course and in its origin it represents the 

 chorda tympani of the higher vertebrates. Cole, who examined 

 these branches in Chimaera, considers the ramus praetrematicus 

 itself as the homologue of the chorda. 



While I leave to those who have made a special study of the 

 subject the many questions of comparative anatomy connected 

 with this matter, I wish to point out merely the fact that the rela- 

 tions in selachians are proofs of the opinion that the tongue as far 

 as the sense of taste is concerned is innervated in toto by fibers 

 terminating in the communis region, a part which in man, was 

 described by Edinger as the taste nucleus. 



Static center. As a counterpart of the greater development of 

 the cerebellum and fasc. long, posterior we find in the sharks the 

 terminal nucleus of the nerve of the lateral line canals of the head 

 very strongly developed and separated from the rest of the static 

 region as a distinct lobe. When describing this center in the bony 

 fishes I have already given a summary of the diflPerent opinions 

 and names which have been current about this lobe and the nerve 

 which terminates in it, so that it may suffice to refer to what I said 

 there. Agreeing with Johnston, I call this lobe, lobus nervi 

 lateralis, applying the name lateral nerve also to the root which 

 innervates the canal system of the head. Perhaps it might be 

 better to term it the lobus staticus, as there can scarcely be any 

 further doubt that we are to regard this lobe as a static center, it 

 is so intimately connected in position, structure and relations with 

 that of the octavus. 



As we see from Figs, cii, ciii, civ, this static nerve enters the 

 brain behind the insertion of the auriculus, running over the cere- 

 bellar crest, which covers the terminal region of the octavus, into 

 the lobus nervi lateralis, which is likewise covered with cerebellar 

 formation, and which it pierces in small bundles. There it 

 divides into ascending and descending fibers which course through 

 the whole length of the lobus. Its terminal region is scarcely 

 distinguishable in structure from that of the region of the octavus 

 itself, with which in the bony fishes it constitutes a single w^hole. 

 Both are also probably put into relation with the motor centers 

 of the oblongata and myel through the fasciculus longitudinalis. 



The posterior lateral nerve, which enters in the region ot the 



