NERVES OF THE DOGFISH 



343 



between the gasserian ganglion and the anterior hyomandibular 

 root are really the lateral-line root of the hyomandibularis, de- 

 rived not from the gasserian ganglion, but from the more dorsal 

 lateral-line roots, those of the lateral-line lobe and the acusticum. 



Fig. 37 A cross-section through the roots of the left facial nerve of Mustelus 

 californicus. X25. 



The dorsal (anterior) and ventral (posterior) lateral-line 

 ganglia in Squalus are sharply distinct from each other, as Land- 

 acre has shown in the 22-mm. embryo. The anterior ganglion, 

 owing to its development around the posterior border of the 



