596 AELLTS. EVOL. 2k 
capsule into that capsule. It enters the brain immediately in 
front of the root of the acusticus, almost as a part of that root, 
the two roots issuing each by two or more rootlets from the 
summit of a slight swelling or eminence on the side of the 
medulla. From its under surface, close to its origin, or pos- 
sibly as a separate root, a large branch is sent downward, 
outward, and forward, to the posterior portion of the main 
trigemino-facial ganglion, where it turns outward and then out- 
ward and backward, traversing the ganglion and issuing as 
part of the truncus hyomandibularis facialis. It forms a large 
part of the posterior bundle already spoken of as traversing the 
ganglion. These two roots, or two branches of a single root, 
together form the sense-organ, or, as it has been called, lateral 
component of the trigemino-facial ganglionic complex. 
Close to and intimately associated with this lateral root arise 
two other bundles which together form the true posterior or 
facial root of the main ganglion. The anterior of the two arises, 
as a bundle, at a high level in the brain, probably from the 
fasciculus communis of Osborne and Strong, and issues in 
front of and internal to the sense-organ root. It enters mainly 
into the median portion of the main ganglion, and from this 
portion arise the ramus palatinus facialis as well as the fibres 
already spoken of that go to forma large part, if not all, of the 
ophthalmicus superficialis trigemini and a considerable part of 
the truncus maxillaris. The other root arises also as a distinct 
bundle deep in the brain, but nearly on the same level as its 
point of exit, which is in front of and below the root of the 
acusticus and below the lateral root of the complex. It is prob- 
ably the motor root VII ab of Strong in Rana, although its 
position is not exactly the same as that given by him. It 
enters the posterior portion of the main ganglion immediately 
in front of the hyomandibular branch of the lateral root, and 
apparently traverses the ganglion with that root, forming 
_ with it the posterior transverse bundle or commissure of the 
ganglion. 
The abducens in these larvae arises immediately behind the 
posterior end of the ganglion of the acusticus, and in my sec- 
tions is at its origin distinguished with difficulty from that 
