30 

 the central termination is comparabJe to tliat of the somatic 

 sensoi-y spinal fibi-es. Part of the general cutaneous fibi-es 

 terminate in the t^.eneral cutaneous nucleus, the homologue in 

 the heaj of the dorsa] cornu; see Subsection ^; but others tur-n 

 into the spinal V tract and take a course posteriorly for ulti- 

 mate termination in the dorsal cornu of the cord. There can 

 be no question as to the identity of this system with the somat- 

 ic sensory system in its siiripler condition. 



c. The Viscero-Votor- Siistett. — Fibres of this system 

 form the motor roots of the V, VII, 1)(, and X nerves. The cell- 

 bodies from vvhich the sxones f^rise form s column of cells later- 

 al to the fourth ventricle, known, according, to the level, as 

 the nucleus ambif-'uus, and the motor nuclei of the VII and V, 

 respectively. This column of cells is the cranial continua- 

 tion of the paracentral nucleus of the cord, and the homolot^y 

 is rendered complete by the distribution of the fibres to the 

 visceral musculature. 



i. The Communii? Si/stem. — This term is used in the sense 

 defined by Herri ok ('99,p.?0?), and as the equivalent of the 

 fasciculus communis of Strong ('95) as applied to the system 

 in the tadpole, and of Kingsbury ('97) as used for various 

 fishes. Communis fibres are components of the VII, IX, and 

 X nerves. They are wholly sensory. They innervate visceral 

 and mucous surfaces, and also taste-buds and those special i7ed 

 sense-organs of the skin (end-buds) not referable to the later- 

 al line system. The fibres are characterised by their snail 



