THE EPIBRANCHIAL GANGLIA OF LEPIDOSTEUS 13 
The infra-orbital ramus, ramus buccalis (figs. 4 to 7), origin- 
ates from the ventral portion of the anterior end of the ganglion 
and pursues a course downward and forward in close contact with 
the skin where it can be followed as a fibrillated cord to a point 
near the anterior end of the optic vesicle. It innervates lateral 
line organs of the infra-orbital line anterior to the position of the 
ganglion. The ramus oticus is represented by a small twig 
arising midway between the anterior and posterior ends ofthe 
ganglion. Itsupplies the last lateral lineorganin the infra-orbital 
line. The twig runs laterally from the ganglion and passes under 
the anterior end of the auditory capsule and can be followed easily 
throughout its whole course at this stage. 
The geniculate ganglion 
The geniculate ganglion is an elongated mass of cells placed 
diagonally in the body with the anterior end situated somewhat 
more ventrally and lying directly on the dorsal surface of the 
pharyngeal pocket (figs. 1 and 8). The anterior end of the 
ganglion lies as far forward as the posterior end of the Gasserian. 
The posterior end of the ganglion rises to the level of the base 
of the medulla and its root enters the medulla along with those 
of the dorso-lateral and ventro-lateral ganglia. 
It is throughout part of its extent (fig. 9) wedged in between 
the dorso-lateral ganglion and the ventro-lateral ganglion, to be 
described in the next section, and its posterior end comes closely 
into contact with the auditory. The geniculate ganglion is 
double in composition. The posterior portion, derived from the 
neural crest, 1s definitely outlined and circular in form andseems 
to be purely general visceral in composition. The anterior end, 
which contains cells derived from the placode, is less regular in 
form and incloses or has attached to its ventral surface and 
resting directly upon the endoderm of the pharyngeal pocket a 
mass of cells which projects laterally giving a ‘‘comma’’ shape 
to the ganglion in transverse section( fig. 8). The laterally pro- 
jecting mass is derived from the epibranchial placode and can be 
distinguished both by its color and position of its cells. The 
