464. LANDACRE AND McLELLAN 
THE GLOSSOPHARYNGEAL GANGLION 
The visceral portion of the IX ganglion is quite distinct from 
the X (figs. 1, 2, 3 and 7). It lies ventral to the ear capsule, 
its anterior end reaching almost to the anterior border of the ear 
capsule. The ganglionic cells disappear posteriorly at the level 
of the middle of the capsule and the ganglion here dwindles into 
a fibrous root which arches around under and behind the capsule 
and at the level of its posterior end ascends to enter the medulla 
at the same level as that at which the roots of the X enter it. It 
was not possible in either the 8 mm. or the 10 mm. stages to iden- 
tify a special visceral, or gustatory portion, in the visceral IX, 
although a more careful study of earlier stages leading up to these 
might enable one to identify it. 
The anterior end of the ganglion at this stage abuts against 
the posterior end of the thymus gland which consists of a dense 
mass of lymphocytes, oval in shape and lying at the same level 
dorso-ventrally as the glossopharyngeal ganglion. In stages ear- 
lier than that figured (figs. 3, 7, 7.G.) the ganglion overlaps the 
gland to a greater extent, usually lying on the dorsal surface of its 
posterior end. These relations are important because of the fact 
that in early stages it is difficult to distinguish between the gland 
and the ganglion histologically, and further, on account of the 
fact that the ramus lingualis of the TX lies on the outer (lateral) 
surface and the pharyngeal ramus lies on the inner (mesial) side 
of the gland. 
At the level of the middle of the ear capsule and at the posterior 
border, situated sometimes on the dorsal portion of the root of 
the IX sometimes surrounding the root, is a small lateralis gan- 
glion which we have designated the lateralis [X ganglion. ‘This 
ganglion, so far as we know, has not hitherto been identified as a 
distinct lateralis ganglion in the frog. Strong, however (95, p. 
144), correctly homologizes the nerve arising from this ganglion 
(the supra-temporalis) with a lateral line nerve of the LX in fishes. 
This is undoubtedly correct, since the ganglion has a separate 
existence from early stages and is only accidentally and quite 
variously related to the lateral line ganglia of the X. 
