SO BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
others [X is independent of both X and XII; these conditions hay 
significance in determining the probable source of the termina 
branches in such a form as Anolis, where these branches cannot b 
followed back through the combined trunk; they will be referre 
to again in the account of the terminal distribution of IX and X 
Since nerve X is larger than IX in all the forms described, its gangli: 
have been more regularly found than those of IX. The trunk gan 
glion of X (gn. nd.) is a more constant feature than its root ganglior 
(gn. rv. X, gn. X), having been described for all species hithert 
studied. On the other hand, the root ganglion, such as is found i 
Anolis, has been definitely identified as an independent ganglion ir 
only three forms. 
3. TERMINAL DISTRIBUTION OF NERVES IX AND X. 
From the foregoing account it is seen that all the components o 
IX and X (excepting the rami to the jugular vein) are distributec 
peripherally from three rami. (1) Jacobson’s anastomosis, carrying 
viscero-sensory fibers to VII; (2) Pharyngo-laryngeal, carrying thé 
superior laryngeal branch of X and the pharyngeal branch of IX 
both of which include viscero-sensory.and viscero-motor fibers 
(3) ramus visceralis, carrying viscero-sensory fibers of X. To wha 
extent efferent sympathetic fibers may be carried in any of these ram 
could not be determined. 
(1) Jacobson’s anastomosis. This term is here used for the com 
municating ramus (comn. 7.) between IX and VII, which joins th. 
base of the ramus palatinus. As the term is generally employed } 
is restricted to a connection between these points, which carries 
viscero-sensory palatine branch from IX to be distributed with pal: 
tine VII, and also innervates the mucous surfaces caudad to VI 
Because of the development of the sympathetic system of the hea 
the main trunk of which takes this course, it is difficult to determir 
to what extent this is a true viscero-sensory branch. In Anolis tw) 
points on VII are connected with IX, usually at the distal end of tl 
petrosal ganglion. This connection is often so slight that it is lo 
sight of in the more evident fact of the direct passage of this symp 
thetic bundle caudad to its ganglion. It is always large enoug 
however, to give rise to all the medullated fibers contained in t) 
internal communicating branch, which is the one having the positi’ 
of Jacobson’s anastomosis. Whether it does give rise to them can 
be stated. It can be stated that if Jacobson’s anastomosis (as 1 
stricted) exists in Anolis, it contains very few viscero-sensory elemen 
! 
