X Journal of Comparative Neurology. 



some fibers of a lateral line nerve accompany the profundus. The sec- 

 ond case discussed by Cole and considered by him more difficult of 

 explanation, is the innervation of a canal organ by a twig from the glos- 

 sopharyngeus in Elasmobranchs, Teleosts and Ganoids. Cole thinks 

 the explanation in the case of the profundus inapplicable here where so 

 many different groups are involved. It may be pointed out here that 

 the difficulty in this last case has been materially lessened by two more 

 recent researches. We know from Kingsbury's researches that in Amia 

 the glossopharyngeus is re-enforced by fibers from the root of the N. 

 lateralis and it is only reasonable to suppose, as Kingsbury points out, 

 that those are the fibers which compose the twig from the glossophar- 

 yngeus to a canal organ. Furthermore, in an examination of serial 

 sections through the head of Squalus acanthias, the writer of this review 

 found that here also fibers passed from the root of the N. lateralis, near 

 its exit from the brain, to the glossopharyngeus. These fibers could 

 be traced as a component of the glossopharyngeus until they separated 

 outside the auditory capsule as a twig to a canal organ. Thus the true 

 state of affairs in this apparent exception really greatly strengthens the 

 view as to the specific character of the innervation of the lateral line 

 organs. It can hardly be doubted that this explanation will be found 

 to apply to the other forms mentioned by Cole. As a slight correction 

 of a statement by Cole that Strong failed to demonstrate this twig in 

 amphibia it may be stated that a twig corresponding to this was shown 

 to arise from the vago-glossopharyngeal complex in the tadpole but that 

 its fibers were found to be derived here also from the root of the N. 

 lateralis. 



The complete exclusion of all the cranial nerves except the special 

 lateral line roots from the innervation of this system of organs being a 

 point of very considerable importance and one to be determined with 

 certainty as a necessary preliminary to further deductions, it may 

 be pointed out here again [vide supra) that Cole, notwithstanding as- 

 sertions apparently to the contrary, has not yet made out a complete 

 case from actual observation. For example, we have that extensive 

 fusion of the profundus with the lateral line nerve, the ophthalmicus 

 superficialis portio facialis. The exact character of the twigs given off 

 beyond this point has not been ascertained from actual observation i. e. 

 it is not demonstrated that those twigs which supply the canal and ampul- 

 lary organs are solely derived from the facial portion of the joint nerve. 

 This fusion is commonly met with in Elasmobranchs and it has not ap- 

 parently been completely analyzed there. The fusion of fibers from 

 the root of the buccal with the hyomandibular described by Cole in 



