516, ALLIS. [Vot. II. 
the facial arise from a Y-shaped mass of ganglion cells, formed 
on the dorsal root of the facial nerve, and lying on top of the 
rest of the trigemino-facial ganglionic complex, closely applied 
to it, but quite separate from it. The ophthalmic branch of the 
facial arises from the inner and upper arm of the Y, and the 
buccal from the lower and outer one. The otic and the branches 
to organs I1 to 14 infra-orbital, when they are not given off by 
the buccal, arise from the external side of the Y, and hence 
seem properly a part of the buccal. If this be so, and Beard’s 
theory is to be accepted, then the original epiblastic thickening 
from which the infra-orbital line to organ 16 is developed, must 
have grown both forward and backward, the buccal being split 
off concomitantly with the growth of the anterior part, and the 
otic with that of the posterior, a few uncertain branches lying 
between them. 
Organ 17 is supplied by the dorsal branch of the glosso- 
pharyngeal. This branch arises by a separate root, which 
passes out of the cranial cavity immediately behind the root of 
the main nerve, and often at this age by a separate foramen, or 
through a special part of the main foramen. On this root a 
separate ganglion is formed close to, and more or less intimately 
connected with, the main ganglion, and from it the dorsal nerve 
mentioned by Wright arises (No. 17, p. 489). This nerve runs 
upward through a special perforation of the chondrocranium, 
and, issuing on the bottom of the temporal groove, sends one 
branch to organ 17, the only canal organ supplied by it, and 
another to the middle dorsal pit line. This last branch runs 
medianward to about one-third the length of the pit line. It 
then turns upward and outward through the dermal bone, and 
dividing somewhat dichtomously, sends one branch medianward 
and another outward, both of them lying immediately under- 
neath the line. From these branches smaller ones are given 
off directly to the separate organs. The innervation of this line 
indicates that it has grown in both directions from the original 
sensory spot found in younger specimens, and also that, although 
supplied by the same dorsal nerve that supplies canal organ 17, 
it is not a continuous growth from the epithelial thickening 
which was the rudiment of that organ. In this it differs from 
the other two dorsal head-lines, which grow from, and are 
directly continuous with, the rudiments of the canal organs 
from which they start. 
