306 H. W. NORRIS 
bined rootlets of this third group form, at the median ventral 
border of the lateral line root a band which, running posteriorly 
parallel with the latter (fig. 14), is joined just before the two roots 
enter the ganglion by the fourth group of rootlets (Xr.3). The 
loose distribution of the numerous small motor rootlets makes it 
possible to distinguish them by their color only. Thus three 
fiber groups enter the [X—X ganglionic mass (1) the lateral line 
root; (2) the glossopharyngeal root, communis and motor fibers, 
to which has been joined the small lateral line contingent from 
the preceding, with its accompanying communis (?) fibers from 
the third group; (8) general cutaneous, communis and motor 
fibers of the third and fourth groups of rootlets. 
Wiedersheim (’77, p. 17) states that Siren is the only urodele in 
which.-the ninth nerve has a foramen of exit distinct from that of 
the vagus. Parker (’82, p. 194) says that ‘‘the glossopharyngeal 
and vagus pass out of a common passage in the exoccipital.”’ The 
writer finds this latter statement confirmed by the condition in 
young individuals. 
2. The IX—X ganglionic mass 
The elongate glossopharyngeal-vagus ganglionic mass, as in 
all Urodela, has its anterior glossopharyngeal end wedged under 
the posterior part of the ear capsule. The glossopharyngeal 
portion (ggl.) is more distinct from the vagal (gv.) than it is in 
most’ other Amphibia. In some instances a separating line is 
distinguishable throughout between the two. The IXth root 
enters the dorso-medial portion of the sub-capsular part of the 
ganglionic mass. Slightly dorsal to the [Xth root the lateral line 
root of the ramus supratemporalis X enters the ganglion; or in | 
some instances it has a small distinct ganglion of its own at the 
antero-dorsal border of the I[Xth ganglion (fig. 39, gspt.). The 
other sensory fibers (X ad IX) entering along with the lateral 
line elements, sometimes, if not always, possess a distinct ganglion 
at the medial border of the [Xth ganglion. Of the peripheral 
destination of these latter sensory elements little more can be 
said than that they apparently enter the ramus posttrematicus 
IX. Whether they are general cutaneous or communis fibers 
