No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 747 
form the so-called dorsal root of the nervus. On this dorsal 
root, in larvae, a separate ganglion is formed, and from it 
arises the dorsal or suprabranchial branch of the nervus, which 
branch is destined entirely to supply certain of the sense organs 
of the lateral system. From the ganglion of the main root 
arise pharyngeal, pretrematic, and posttrematic branches, which 
have the distribution indicated by their names. The ramus 
pharyngeus and ramus pretrematicus traverse regions where 
terminal buds are found. No branch of the nervus could be 
traced definitely to the pseudobranch. 
24. The vagus arises by several roots, all of which traverse 
an intracranial ganglion, and then separate into four portions, 
on each of which an extracranial ganglion is formed. From 
each of the first three of the latter ganglia arise pharyngeal, 
pretrematic, and posttrematic branches ; from the fourth arise 
the superior and inferior pharyngeal nerves, and the nervus 
intestinalis. The pharyngeal branches of the first three nerves 
pass downward, to their destination, between the articular and 
interarcual ligaments that connect the infrapharyngobranchial, 
or epibranchial, of the arch of the nerve, with the epibranchial 
of the next preceding arch. 
From the anterior fibres of the root of the nervus, or in part 
from its intracranial ganglion, a supratemporal branch arises, 
which accompanies closely the supratemporal branch of the 
nervus lineae lateralis, and is distributed to regions where 
terminal buds abound. A part of this nerve fuses completely 
with a branch arising from one or both of the first pair of 
dorsal branches of the ramus ophthalmicus superficialis trige- 
mini. Another branch, arising from the base of the nerve, or 
perhaps from the main vagus root itself, has an intracranial 
course, and issues on the top of the cranium, about where the 
ramus lateralis trigemini, or ramus recurrens facialis, of other 
authors issues. It may represent that nerve or a part of it, 
the rest of the nerve being represented in the main supra- 
temporal branch of the vagus, or in that nerve and the two 
branches of the ophthalmicus trigemini together. 
25. Terminal buds are said to represent a condition through 
which the canal organs of the lateral lines have passed in 
