74 THE ANATOMY OF VEETEBEATED ANIMALS. 



abducens, are more or less confoimded witli the ophtLalmic 

 in the Amphibia ; but in Teleostei, Ganoidei, Elasmobranchii, 

 and in all the higher Vertehrata, the nerves of the muscles 

 of the eye are distinct from the fifth pair, except where the 

 oculomotor unites with the ophthalmic into the ciliary 

 ganghon. 



The facial and the trigeminal nerves have common roots 

 in fishes. In Amphibia, though the roots are distinct, the 

 facial may be completely united with the ganglion of the 

 trigeminal, as in the Frog. In all abranchiate Vertehrata 

 the two nerves are quite distinct. 



Whether the nerves are distinct or not, a palathie, or 

 vidian, nerve (which, in the higher Vertehrata, is especially 

 connected with the facial) runs through, or beneath, the 

 base of the skull, parallel with its long axis; and, after 

 uniting with the superior maxillary, and usually contri- 

 buting to form the sphenopalatine, or Meckelian, ganglion, is 

 distributed to the mucous membrane of the roof of the 

 mouth; and the mandibular division of the seventh, or 

 chorda tympani, unites with the inferior maxillary division 

 of the fifth nerve. 



The eighth pair fauditoriij is formed by the nerves of the 

 organ of hearing. 



The ninth pair fglossopharyngeij is especially distributed 

 to the pharyngeal and lingual regions of the alimentary 

 canal, and, primarily, supplies the boundaries of the second 

 visceral cleft. 



The tenth pair (pnewmogastrici or vagi) consists of very 

 remarkable nerves, which pass to the giUlet and stomach, 

 the respiratory and vocal organs, to some parts of the 

 integument of the body, and to the heart. In the Ichthyop- 

 sida they give off, in addition, long lateral nei-ves to the 

 integuments of the sides of the body. In the higher Verte- 

 hrata, these lateral nei-ves are re]presented only by small 

 branches distributed chiefly to the occipital region. The 

 ninth and tenth pairs are both motor and sensory in func- 

 tion, and are often so intimately connected as to form almost 

 one nerve. 



