134 NERVE COMPONENTS OF BONY FISHES. 



2. — T]ie General Cittaneoiis Root. 



Immediately upon entering the brain the sensory root 

 of the trigeminus divides. One part joins the motor V to 

 form the deep root {d. V, Fig. 20) and goes to the chief 

 sensory trigeminal nucleus. The larger part turns caudad 

 and forms the whole of the pre-vagal spinal V tract. Its 

 internal course has been described in Section 3. It 

 crosses the motor trigeminus root and forms the most 

 dorsal member of the V + VII root complex. It is then 

 crossed externally by the dorsal lateralis root and ganglion. 

 The Gasserian ganglion lies farther cephalad than any of 

 the other members of this complex. Its cells resemble 

 those of the geniculate ganglion, though the largest ones 

 are rather larger. 



III. — Comparative Review of the Trigemino-Facial Roots. 



Stannius enumerates forms with five and forms with 

 four roots in the trigemino-facial complex and considers 

 the latter as the more characteristic of fishes, counting 

 the two lateralis roots as one. His analysis of these roots 

 is remarkably exact, more so than those of some more 

 recent writers who have had better methods at their dis- 

 posal. Comparing Menidia with his forms with five roots, 

 it appears that his first root is our general cutaneous plus 

 motor V, z. e., as he states, the trigeminus in the strict 

 sense; his second root is our dorsal lateralis root; his 

 third root, our ventral lateralis root; his fourth root, the 

 communis root; and his fifth root is our motor VII. 



Goronowitsch's endeavor in both the earlier ('88) and 

 the later ('96) papers to elaborate a simple serial arrange- 

 ment of dorsal and ventral roots of which the several 

 pairs should be strictly homodynamous with each other 

 and with spinal roots must be reckoned a total failure, as 



