326 H. W. NORRIS AND SALLY P. HUGHES 



of the ramus ophthalmicus superficialis V enter the gasserian 

 ganglion to become ganglionated. The further destination of 

 the latter fibers is uncertain. 



The gasserian ganglion is partly extracranial, extending out 

 ventrolaterally from the brain wall, and in consequence is dumb- 

 bell or hour-glass in shape, the intracranial part being somewhat 

 larger (fig. 33, gg., gmx.). This peculiar shape of the ganglion 

 is due to the proximity of the lateral-line ganglion and the 

 rectus lateralis muscle. From the proximal intracranial portion 

 the mandibular and superficial ophthalmic rami arise, and from 

 the distal portion the maxillary ramus (figs. 21, 22, and 24). 

 Whether any of the sensory fibers of the portio minor belong to 

 the gasserian ganglion is uncertain, but Landacre believes those 

 of the third rootlet do. The gasserian ganglion is in contact 

 anteriorly with the base of the profundus ganglion and the rectus 

 lateralis muscle (figs. 16, 31, and 33), dorsally with the lateral- 

 line roots of the facialis nerve (figs. 16 and 24), laterally with the 

 dorsal lateral-line ganglion and root (fig. 16), and dorsolaterally 

 with the dorsal lateral-line ganglion. Unlike the condition in the 

 22-mm. embryo, as described by Landacre, the emergence of the 

 fibers of the ophthalmicus superficialis V does modify the form 

 of the gasserian ganglion. Distal projections of small ganglionic 

 masses are seen to be related to parts of the ramus ophthalmicus 

 superficialis V (figs. 16 and 31). 



In Mustelus the fifth nerve possesses three ganglia, merged 

 posteriorly, as Allis finds, but nevertheless distinct: a dorsal 

 ganglion of the r. oph. spf. V, a lateral profundus ganglion, 

 and a ventral maxillomandibular ganglion. The first two of 

 these are intracranial; the maxillomandibular ganglion is largely 

 intracranial, but a considerable portion, as in Squalus, extends 

 out through the trigeminal-facial foramen into the ventral por- 

 tion of the orbit. Figure 23 is a projection upon the sagittal 

 plane of the ganglia of the V-VII-VIII complex in Mustelus 

 californicus, showing the relative independence of the several 

 ganglia. At no place is there any difficulty in distinguishing 

 between the trigeminal and facial ganglionic elements. 



