OF THE HEAD IN THE BATRACHIA URODELA. 



105 



and the overlying squamosal, and passes down the hyoid arch. The 

 glossopharyngeal and vagus come out together behind the auditory 

 capsule — the former supplying the first branchial arch, and the 

 latter giving off three branches to the remaining ai'ches. A large 

 viscei'al branch of the vagus runs along the alimentary canal, a 



Text-fio-. 30. 



Outline of spinal cord and hind brain, with roots of cranial nerves and first tvvo 

 spinal nerves, seen from left side. 



dorsal branch upwards, and slender latei'al line branches to the 

 skin. Through the bony neural arch of the first vertebra issues 

 the first spinal nerve, having a. ventral root only. Passing over 

 the vagus it soon joins the complete second spinal, which has 

 two roots *, and comes out behind the first vertebra. A dorsal 

 twig of the first spinal supplies the temporal muscle. The first 

 and second spinals together make up the hypoglossal nerve. 



spg 



Partial reconstruction of the hind region of the skull and the anterior region of 

 the trunk of an advanced larva with a head 6 mm. long. The cai'tilaginous 

 skeleton and nerves are shown through the myotomes. 



Text-figs. 31 and 32 are partial reconstructions of a larva which 

 has nearly acquired the structure of the fully grown animal. 

 The auditory capsule is chondrified and fused to the basilar plate, 



* Miss Piatt finds only a ventral root to this nerve in Xcctio-ifs. Thcvf cuii be no 

 doubt that both roots arc present in Amb/i/sfoma as well as a ganglion. 



