136 NERVE COMPOjSTENTS OF BONY FISHES. 



foramen, it crosses a ganglion of the sympathetic chain 

 (Fig. 21, sj>.) and may derive some fibres from it. After 

 emergence from its foramen it runs outward to the 

 hyomandibular bone and then turns abrubtly ventrad and 

 slightly caudad, entering a canal in that bone. 



At this point, z. e., just as the tnmcus is turning ven- 

 trally and some distance outside of the foramen, it receives 

 on its caudal face a considerable bundle of fine fibres 

 which come from the Gasserian ganglion. See Fig. 4. 

 Their course is as follows : The truncus hyomandibularis 

 and the r, palatinus together issue from a foramen which 

 is distinct from that of the V nerve and the remainder of 

 the VII. But a small portion of the Gasserian ganglion 

 extends far caudad nearly to this foramen. Here there is 

 a separate foramen in the cranial wall just cephalad of 

 that of the truncus hyomandibularis through which there 

 passes a large blood vessel and also a narrow tongue of 

 ganglion cells belonging to this caudal tip of the Gasser- 

 ian ganglion (Fig. 2, G). From this little extra-cranial 

 ganglion a considerable bundle of fibres passes out later- 

 ally (510) until it reaches the hyomandibular bone (Figs. 

 2,4,/. /. 2). It then turns caudad and ventrad and is soon 

 joined by another similar bundle of fine fibres (Figs. 2, 4, 

 t. f. i) which is derived from the extreme cephalic end of 

 the Gasserian and which emerges from the cranium with 

 the great infra- orbital trunk, curving back and pursuing a 

 tortuous and rather peculiar course, which will be more 

 fully described in connection with the infra-orbital trunk. 



The combined general cutaneous component now passes 

 back and joins the truncus hyomandibularis on its caudal 

 face after it has entered the canal in the hyomandibular 

 bone and begun to turn ventrad (530). Beyond this point 

 it can be separately followed in the truncus with great 



