to BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
marked tract posterior to the sensory root of nerve VII and, as in 
the case of nerve X described below, the fine-fibered sensory root of — 
IX passes directly to this tract. What is stated regarding the motor 
components of [X would apply equally well to nerve X. ; 
The combined roots pass out of the cranium by way of the recessus — 
scalae tympani between the ear capsule and the basoccipital bone, 
Versluy’s (’98, p. 180) general statement applies to Anolis on this 
point: “Bei allen Lacertilia vera tritt demnach der Nervus glosso- 
pharyngeus nicht durch ein eigenes Loch in der Paukenhéhle, sondern 
durch eine grosse Oeffung, welche die altern Autoren meist Fenestra 
rotunda, die neuern Foramen jugulare externum genannt haben.” 
The root passes caudad underneath the mucous membrane to its 
ganglion (Plate 7, figs. 20-23). This, the ganglion petrosum (gn. IX), 
as compared to the root ganglion of the vagus, has a much more distal 
position on its root (Plates 2, 3), and probably represents the trunk 
ganglion of X, inasmuch as there has been described in other forms 
a root ganglion in addition to the petrosum. This ganglion occupies 
the free space between the other organs on a level with the posterior 
edge of the ear capsule (Plate 7, fig. 23). Its form is that of a uniform 
oval, and it lies on the dorsomedian side of its fiber bundle, which it 
incompletely surrounds. 
The coarse motor fibers may be traced directly through this bundle 
and out into the nerve trunk beyond. They have the most ventral 
position — that farthest removed from the ganglion cells — in their 
course through the ganglion. The other fibers seem to be non-medul- 
lated within the ganglion, but this appearance may be due to absence 
of impregnation by the osmic acid. 
Between the ganglion of IX and the union of its main trunk with 
XII there are connections with X and with the sympathetic system. 
These vary in their position, as study of several series of sections has 
shown, although certain relations are quite constant. In the series 
plotted (Plates 2, 3) the anastomoses are relatively simple. The 
frontal projection (Plate 2, fig. 4) is the only one that shows them. 
These will be described first and the variations referred to later. 
A very small bundle of fibers from the vagus (Plate 3, fig. 7; comm. 
IX—X) enters the petrosal ganglion on its proximal side; these become 
entirely mingled with fibers of IX so that the two are not separable — 
beyond the limits of the ganglion. When the bundle emerges from 
the ganglion as the main trunk of IX, it shows in cross section six Or 
eight coarse motor fibers, which have been followed from the motor 
root above described; the rest are very fine fibers, but with sharply 
