114 JOHN BEARD. 
branchial sense organs. So far as my researches go there is a 
wide difference both in morphology and development between 
the cranial and spinal nerves. 
The mode of development of the lateral nerve here described 
is, as previously mentioned, in the main the same as that 
ascribed to it by Van Wijhe. The only author who has 
assigned to it a different origin in Elasmobranchs is Balfour, 
who was inclined to the view that the nerve really grows back- 
wards from the vagus ganglion. 
My own researches on Teleostei! led me to accept Balfour’s 
view, but since I have had the opportunity of investigating the 
matter in Elasmobranchii I conclude that my interpretation of 
the matter in Teleostei was erroneous. 
No doubt the account given by Hoffmann? of the develop- 
ment in Teleostei is correct. It accords well with the facts as 
recorded for Elasmobranchs here and by Van Wijhe. 
But none the less, it may not be superfluous to point out 
that the existing accounts of the development of what I have 
called supra-brauchial nerves in Teleostei, Elasmobranchii, and 
Amphibians—that is, the accounts given by Semper, Gotte, 
Hoffmann, and Van Wijhe, contain in them one element of 
uncertainty. That is, as to how the nerve thus developed from 
the skin acquires its connection with the appropriate ganglion. 
Most of the accounts are quite silent on this point ; Gotte, it 
is true, recognised the importance of the matter, and stated 
that the nerve in any particular case separates from the skin 
along part of its length and grows to its ganglion. This view, 
however, is not in accordance with the facts, and I have 
reason to believe that Prof. Gotte has now himself ceased to 
hold it. 
The apparent absence of connection between the nervous 
structures of the brain and the branchial sense organs of the 
head was to Balfour a great objection to Gotte’s and Semper’s 
view. He said, and to a certain extent he was right, that at 
1 Op. cit. 
2 Hoffmann, ‘Zur Ontogenie der Knochenfische,” ‘ Archiv fir Micros. 
Anat.,’ Bd. xxiii, p. 45. 
