144 AYERS. [Vol. VI. 



and Bufo. It will thus be seen that the facial may arise (ap- 

 parent origin) dorsal or ventral to the VIII. 



(P. 606.) "That the large sensory root of the facial, dorsal 

 to the auditory (dorsal VII), together with the antciior root of 

 the glossopharyngeal, form a distinct group by themselves, dif- 

 ferentiated from the others by their internal origin and by the 

 characters of their fibres, and belonging distinctly to the organs 

 of the lateral canals.^ It is possible that the auditory may have 

 some relation to this system of nerves." 



The so-called anterior root of the IX, according to Strong, 

 usually arises some distance cephalad of the other roots, and 

 also much more dorsally ; its fibres are apparently all sensory, 

 and its deep origin is not determined definitely, though its 

 fibres go through the nuclei of the IX and X. "It is to be 

 regarded as the lateral nerve, and, in respect to the origin of 

 its fibres, their character and distribution, it agrees with the 

 dorsal VII." 



Strong concludes : " It is obvious that the connection of the 

 dorsal VII with the lateral sense organs affords an explanation 

 of its disappearance in adult Anura." 



In Cryptobranchus, according to Osborn {loc. cit. p. 65, and 

 PI. V, Fig. 21), " the glossopharyngeus arises from four sources : 

 I. The fasciculus communis. 2. The large sensory nucleus. 

 3. A nucleus of doubtful motor cells. 4. A motor nucleus in 

 the floor of the fourth ventricle. In Fig. 21 are shown the two 

 nuclei belonging to the auditory nerve. Cne of these, the pale 

 nucleus, lies dorsad and anterior to the other, which is placed 

 more ventrally and internally, and is in close relation with the 

 anterior glossopharyngeal nucleus." 



Our author says {loc. cit. p. 66) : " It is seen that whatever may 

 prove to be the peripheral distribution of the fibres of the fas- 

 ciculus communis and posterior longitudinal fasciculus, whether 

 to the 7th or 8th, two facts remain : first, that the 8th arises 

 ventral to the 7th, although a purely sensory nerve ; second, it 

 is inserted in the centre of the facial-trigeminal system, with no 

 apparent homology in the arrangement of its nuclei to either." 

 As regards the branching of the nerves on the utriculus and 

 sacculus in the lower Amphibia, e.g. Proteus, it takes place 

 much the same as has been described for Elasmobranchs, ex- 



1 See Recapitulation B. 



