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the vagus arises by five main roots, of which the most anterior is the 
root of the lateralis. The next three roots are those of the three 
branchial nerves which supply the posterior demi-branch (or third) on 
the first branchial arch, two demi-branches on both the second and 
third arches, and a single demi-branch on the anterior face of the 
fourth branchial arch. There are thus five gills, of which the first 
and last (on the hyoid and fourth branchial arches) consist of a single 
demi-branch only, and the remaining three of two demi-branchs each. 
The posterior root of the Xth is that of the intestinal.” 
Mr. CoLLInGE classifies the groups of ampullae as follows (my 
own names are given on the right):— 
1) Occipital group 
2) median group == superficial ophthalmic group 
3) supra-orbital group 
4) sub-orbital group == inner buccal group 
5) maxillo-mandibular group = outer buccal group. 
As 1, 2, 3 are all innervated by the superficial ophthalmic division 
of the VIIth, I see no reason for breaking them up, and therefore 
describe them as one group which consists of a very large and 
much smaller portions. I am in some doubt as to the identity of 5. 
Mr. CoLLinGeE describes it as being innervated by the “inferior maxil- 
lary” nerve, and I therefore conclude that it corresponds to my outer 
buccal nerve and group. Mr. CoLLINGE has accordingly overlooked 
the hyomandibular and external mandibular groups of ampullae, un- 
less the following applies to the latter: “Where there are a few 
scattered ampullary canals in the mandibular region, branches of the 
ramus mandibularis (V) innervate them.” I do not think Mr. CoLLINGE 
can have seen the external mandibular group of ampullae, since, 
a) it is a very well defined group, and b) there can be no doubt as 
to its innervation from the external mandibular division of the VII th. 
Mr. CoLLingE describes three types of ampullary canals, which 
may correspond to the three types of ampullae described in my pre- 
liminary paper. I have not specially investigated the ampullary canals, 
so that the following remarks must be taken as suggestions rather 
than criticisms. I think it may be found that Mr. CoLLınge’s “oc- 
cipital pores” lead by long tubes and terminate in what in my abstract 
I describe as “compound” ampullae innervated by the superficial 
ophthalmic division of the facial and belonging to that group of am- 
pullae. If this is not the case, then I have entirely overlooked Cor- 
LINGE’s occipital group of ampullae. He states and figures these 
canals as having practically no ampullae. Owing to the most ventral 
