CRANIAL NERVES OF CAECILIANS 491 



spinal nerves, both of which anastomose with the sympathetic 

 trunk. The syinpathetic chain begins anteriorly with branches 

 from the Gasserian and facialis ganglia. In the region of the 

 ,first spinal nerve is developed a large cervical sympathetic gan- 

 glion, with which a large branch of the vagus anastomoses. The 

 first spinal nerve enters this cervical ganglion and on emerging 

 fuses with a branch of the second spinal nerve to, form the hypo- 

 glossal nerve. Three other sympathetic ganglia posterior to the 

 cervical are figured. With" the sympathetic cord he believes the 

 spinal nerves anastomose. 



Retzius ('81) is unable to find an auditory nerve in Caecilia 

 .(Siphonops) annulata, unless certain rudimentary tube-like 

 structures represent it. 



Waldschmidt ('87) rejects Wiedersheun's assumption of the 

 spinal nerve homology of the olfactorius in the caecilians. In 

 Siphonops annulatus he finds an oculomotorius which he believes 

 to anastomose with the ramus maxillaris V. The rest of the 

 oculomotor nerve he thinks supplies the compressor muscle of 

 the orbital gland, one of its branches combining with a small 

 branch of the ramus maxillaris V. He fails to find a trochlearis 

 or an abducens nerve. He agrees with Wiedersheun as to the 

 general structure of the trigeminus, but finds a fine cutaneous 

 nerve arising apparently from the Gasserian ganglion, which, on 

 the whole, seems to him to correspond to a lateral line nerve 

 (ramus ophthalmicus superficialis VII) of larval amphibians and 

 fishes. He finds what he considers the ramus palatinus VII. 

 Of the existence of a functional acusticus he is not certain. The 

 ganglion of the vagus nerve fuses with a sympathetic ganglion, 

 and the vagus trunk sends anastomoses to the sympathetic 

 chain and to the hypoglossus. 



The Sarasins ('90) find the auditory nerve characteristically 

 developed in Ichthyophis glutinosus. The ventral division of the 

 olfactorius supplies Jacobson's organ. 



Burckhardt ('91) compares the olfactorius of Ichthyophis with 

 that of the Urodela in general and finds no fundamental differ- 

 ences, the double nature in the caecilians being but an exaggera- 

 tion of the general amphibian relationships of the olfactorius. 



