268 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



as is usual in these ganglia, are very small and not 

 crowded, being scattered among the nerve fibres. 



The dorsal lateral line root, as already described, has 

 a discrete ganglion, and a reference to the chart will show 

 that the communis, ventral lateral line and motor roots 

 enter the ganglionic mass above by two nerve bundles. 

 The anterior one is the communis root and the posterior 

 represents the ventral lateral line and motor roots fused 

 together, the motor fibres of course having no connection 

 with the ganglion cells. The entry of the trigeminus root 

 into the Gasserian ganglion is described above. 



Leaving the compound ganglionic mass are three 

 large nerve trunks : (1) the Tr uncus supraorbitals ; (2) 

 the Truncus infraorbitalis ; and (3) the Truncus hyo- 

 mandibularis — all compound trunks into which both 

 trigeminal and facial nerves enter. It will be seen on 

 reference to the chart that the last is formed by three 

 nerve bundles from the ganglionic mass uniting together. 

 The most anterior of these arises from the Gasserian 

 ganglion and thus forms the trigeminal cutaneous vii. 

 component of the hyomandibular trunk. In Menidia the 

 cutaneous vii. is extracranial, and is formed by two 

 bundles from the Gasserian ganglion fusing together. In 

 the Plaice there are one large and two very small bundles 

 — all intracranial. The middle of the three nerve bundles 

 above is the communis root, and the posterior the fused 

 ventral lateral line and motor roots. The motor vii., as 

 mentioned above, joins the ventral lateral line root proxi- 

 mal to the ganglionic mass. At first they remain distinct, 

 the motor vii. lying on the outer face of the ventral lateral 

 line ganglion. Before leaving the ganglion, however, the 

 two roots become almost too intermingled to be 

 distinguished. 



Before proceeding to describe the divisions of the vth 



