114 
supposed to represent the nucleus ambiguus. The fibres 
of this system are heavily myelinated. 
5. Acustico Lateral System.—Includes the auditory 
and lateral line nerves. Let it be emphasised at once, 
what is taking a long time to filter down into the text- 
books, that the lateral line nerves can only be associated 
with two cranial nerves—the vith and xth. The lateral 
line fibres in the fifth nerve are always derived from the 
facial, those in the ixth (when present) from the vagus. 
The fibres of this system are distributed to the ear, to the 
sense organs in the lateral line canals, and to those lateral 
line sense organs lying free on the skin, and known as 
pit-organs. Its ganglia are the dorsal and ventral lateral 
ganglia of the facial, and the lateralis ganglion of the 
vagus, and its fibres are very large, being in fact the 
coarsest in the body. Its central termination is the tuber- 
culum acusticum of the antero-dorsal region of the 
medulla—associated with the cerebellum. The hyper- 
trophy of the lateral line nerves produces an exaggeration 
of the tuberculum acusticum well marked on the surface 
of the brain and called by Johnston the Lobus, linez 
lateralis. This lobe has also been called the Lobus trigemini 
by the older writers, and when associated with lateral line 
fibres it may well receive the name given it by Johnston. 
Otherwise it should be called the Lobus facialis (see above). 
Nervus Olfactorius*—I. (Figs. 25 and 28.) 
As considerable asymmetry is exhibited by these 
nerves, both sides will be described. 
*For the cranial nerves of Teleostean Fishes compare especially the 
following works ;—Allis (Amia), Jour. Morph., ii. and xii. ; Cole (Gadus), 
Trans. Linn. Soc., ser. 2, vii.; Desmoulins and Magendie (nerves of 
Rhombus), Anat. Syst. Nerveux, Paris, 1825; Herrick (Menidia, Gadus, 
and Amiurus), Jour. Comp. Neurol., ix., x., and xi.; Juge (Silwrus), Rev. 
Suisse Zool., vi; and Stannius (general), Rostock, 1849. The works of 
Herrick are most important so far as the Plaice is concerned, and should 
certainly be consulted. We have purposely adopted, as far as possible, the 
same reference letters, in order that the comparisons may be facilitated. 
aes 
