THE HYOMANDIBULAR TRUNK. I35 



he has not taken into account the qualitative differences 

 in the fibres of these roots. The second paper is domin- 

 ated by this attempt quite as much as the earHer one and 

 Strong's suggestion ('95, p. 168) that the ventral root of 

 Trigeminus II is not motor but sensor}^ (lateralis) is re- 

 jected. Nevertheless the papers of Kingsbury ('97) and 

 Johnston ('98) both show that in Acipenser the composi- 

 tion of these nerves is just as in Menidia, viz., Trig. I is 

 the general cutaneous and motor V roots, Trig. II is the 

 two lateral line roots of the facial nerve, and the facial of 

 Goronowitsch is the communis and motor VII roots. See 

 sub-section XII beyond. 



IV. — The Truncus Hyomandibularis. 



This nerve receives all of the motor VII root, all of the 

 fibres from the ventral lateralis ganglion, a bundle of 

 communis fibres from the geniculate ganglion, and a 

 bundle of general cutaneous fibres from the Gasserian 

 ganglion. Of these the lateralis component is by far the 

 largest, the motor bundle is about one-fifth as large, while 

 the other two components are about as large as the 

 motor. The motor fibres join the lateralis root from the 

 ventral side snd mingle with them. Beyond the lateralis 

 ganglion several small bundles of fine communis fibres 

 are derived from the geniculate ganglion (not shown on 

 any of the plots) . Still farther cephalad and just as the 

 truncus is passing through its foramen it is crossed by the 

 large r. palatinus and from the latter receives a large 

 bundle of communis fibres. These constitute a compact 

 bundle on the cephalic face of the truncus and as such can 

 be followed almost the entire length of this nerve, con- 

 stituting peripherally the r. mandibularis internus VII. 



As the truncus hyomandibularis is passing through its 



