128 JOHN BEARD. 
of the so-called organs of the lateral line, and rejects Marshall’s 
view entirely. 
Although I have very little that is new to add concerning 
the development of the olfactory nerve, still the novel way 
in which its development will be regarded is not without 
importance. 
It was seen in discussing the nerve of the second segment— 
the root of the ciliary ganglion—that the whole nature of the 
nerve of this segment was obvious enough when it was noticed 
that the musculature of the lateral plates, that 
is, the gill musculature, was absent, even in the 
ontogeny. 
As a consequence post-branchial and prex-branchial 
nerves were absent, and the whole segmental nerve was 
reduced to a ganglion and a supra-branchial sensory nerve. 
This nerve, as its name implies, being connected with the 
innervation of the still existing branchial sense organs. Of 
course the main stem of the nerve connecting ganglion and 
brain was also present. 
A very similar condition of things exists in the nose. The 
early development has its exact parallel in the development of 
the nerve of the second segment. The sole difference is that 
the sense organs of the nose have not, as in the case of those 
of the second segment, undergone further development in a 
linear direction (fig. 46) but have confined that development 
to a somewhat circular area. That is, they have developed 
in many directions, but to a limited extent in each. A change 
of function has also probably occurred. In higher forms, this, 
of course, is certain. 
A glance at the diagram (fig. 46) will illustrate the meaning 
of the above remarks. The supra-branchial nerve of the second 
segment (s.d.n.) is represented by a line. In the nose 
(olf. 0.) a supra-branchial nerve can hardly be said to be 
present. The sense organs have developed within an enclosed 
figure. 
For the rest, the development of the nerve of the first seg- 
