266 G. E. COGHILL 



along the ventral aspect of the fasciculus solitarius to the level 

 of about the middle of the auditory vesicle (fig. 6). 



3. The glossopharyngeal and vagus nerves 



This complex includes lateral line, general cutaneous and vis- 

 ceral components. 



A. THE NON-MOTILE STAGE 



1. The lateral line component. There are two postauditory 

 lateral line primordia (Paper I, fig. 56, Po.LL.l and 2). The one 

 of these is closely associated with the ectodermal thickening over 

 the first branchial pouch; the other lies along dorsally of the 

 thickening of the ectoderm in the vicinity of the more caudal 

 pouches. From the primordium over the first branchial pouch a 

 slender strand of cells reaches to the brain (fig. 1, G.L.L.IX, 

 R.L.LJX,X). These cells are laden with yolk spherules and are 

 mostly of an indifferent nature, although some of them have the 

 appearance of neuroblasts. This is the lateral line ganglion of 

 the glossopharyngeus. While the root reaches the brain, nothing 

 can be determined concerning its fibers within the brain. 



The main lateral Une ganglion of the vagus is a spindle-form 

 body, situated opposite the first and second myotomes. It has 

 a broad attachment with the lateral line primordium of that 

 region. Its root is so slightly developed that it can be recog- 

 nized only as it lies in the plane of section. A very few root 

 fibers reach the brain in connection with the lateral line root of 

 the ninth nerve (fig. 1, G.L.L.X). 



2. The general cutaneous component. On the lateral aspect of 

 the lateral line ganglion of the vagus is a loose aggregation of 

 cells which extends caudad into very close relation if not into 

 contact with an ectodermal thickening which is practically con- 

 tinuous with the lateral line primordium associated with the 

 vagus nerve. This cluster of cells, representing the jugular 

 ganglion of the vagus, is slightly more condensed in its most 

 rostral portion, which bends mesad ventrally of the lateral line 



