464 Grace B. Watkinson 
a) Ramus reeurrens nervi trigemini ad facialem is described 
under nervus trigeminus!. 
b) Chorda tympani is given off from ramus hyomandibularis 
shortly after the latter has crossed the columella auris. Its course 
is first a short distance posterior, elose to the columella auris, after 
which it turns anterior, and runs over the columella to the qua- 
drate bone where it takes a second turn, this time ventrally, Iying 
close to the posterior surface of the quadrate bone, and thus makes 
the eireuit of the anterior wall of the middle ear. It passes inter- 
nally to the posterior end of the pterygoid bone, enters the canal 
in the os articulare of the mandible, and runs through this canal 
anteriorally to join with ramus mandibularis V. in the inferior alveolar 
canal in os dentale. 
ec) Ramus eommunicans externus eum glossopharyngeo is given 
off from ramus hyomandibularis slightly posterior to the origin of 
the ehorda tympani and joins the ganglion petrosum of glosso- 
pharyngeus. 
d) Ramus digastrieus comprises a large portion of the end divi- 
sion of ramus hyomandibularis. This branch continues from the 
main stem direetly posterior and breaks up into many fine branches 
in the muscle. Some of the branches pass entirely through the 
musele, others median to it. These are: 
e) Rami ad M. constrietor colli. (This musele is also innervated 
by the second cervical nerve which forms a sling with the end 
fibres of nervus VII in m. constrietor colli.) 
(f) Ramus hyoideus. I could find no trace of a branch from 
ramus digastrieus to m. mylohyoideus as deseribed by Rue. This 
muscle seemed to be innervated entirely by a fine branch from 
ramus alveolaris inferioris V., but I cannot be certain that there 
was not also a fine branch from VII.) 
VIH. Nervus acusticus arises from the lateral line of the 
medulla oblongata, immediately posterior to VII. Entering at once 
into the cavity of the inner ear through the meatus auditorius 
internus, it divides into two main parts: 
! In several specimens a curious arrangement was observed in regard to 
the junetion of this branch with the main stem of ramus hyomandibularis. 
Instead of joining the nerve itself, this branch joined the middle point of a 
small branch of about equal fineness as itself, which ran from the main stem 
of the nerve to the chorda tympani near the origin of the latter, so that tlıe 
small branch thus formed a loop through which the artery passed. 
