47 
on this question. It is sufficient to refer readers to p. 154 ete. of my 
Gadus paper. Inote that Aruıs does not endeavour to meet the objection 
that I urged against his view of the matter. — As to Arcock’s work on 
Ammocoetes Auuis says: “I consider [it] a valuable contribution to our 
knowledge of the lateral sensory system, differing radically, in this, with 
Core.” This is hardly correct. I did not doubt that the work in question 
had been carefully and ably conducted, and only strongly criticised the 
primature conclusions based on that work. It will be remembered that 
my principal objection was that we knew nothing of the status of the so- 
called lateral line organs of Arcock, and they could not hence be used 
as a basis for discussion. The very same objection was emphasized by 
another worker on cranial nerves in a letter received before my criti- 
eism was published. Further my criticism was accompanied by at least 
some evidence, whereas the only point Aurıs urges for his opinion is 
as follows: “The ventral line of epidermal pits in Ammocoetes, for 
example, a part of which is said to be innervated by a branch of the 
ventral branch of the glossopharyngeus, explains, in all probability the 
gular line of pit-organs im Amia, a line of organs doubtless overlooked 
by Core in his statement that ‘the ventral line from the IXth backwards 
is not represented in other recent or fossil Fishes’.” I beg to say I 
did not overlook the organs in question, but as their innervation was 
not “fully determined” (see fig. and text) in Auuis’ first Amia paper, 
and as I did not find any branch of the IXth described as supplying 
them in his second Amia paper, I considered their nature of too 
doubtful a character to have any value in the discussion. — With 
regard to the nerve I identified as the otic branch of Ammocoetes, such 
identification may be wrong, but it is based on a comparison with 
Selachians, and therefore has more a priori probability than the sug- 
gestion of Aruıs. It is a common practice on the part of the latter 
to interprete all fishes in terms of Amia — a specialised fish it must 
be remembered of a family going no further back than at most the Jurassic. 
— The last paragraph of the criticism is easily met. It is in my opinion 
gratuitous to doubt Jounsronn’s work in this particular connection, as 
lateral line fibres are easy to identify, and Jounsrone& actually did not err 
in his identification of the roots of the IXth, which are in fact, omitting 
the olfactory and optic nerves, the easiest roots to identify in a fish. 
Moreover the peripheral distribution of the nerves of Acipenser has been 
carefully described. Omitting the well-known work of GORONOWITSCH, it is 
sufficient to mention the admirable account of Stannius published in 1839. 
That he considered this work to hold good is obvious from the preface 
to his 1849 memoir, and the latter Aruıs, like the rest of us, holds in 
great admiration. The 1839 work is however not quoted either by 
JOHNSTONE or ALLis, but as the main results figure in the general 
memoir well known to both, I hold that Jonnsronn’s data were fully 
sufficient for this particular purpose (i. e. the IXth nerve), and see no 
reason to doubt his statements — except a controversial one. As to 
Kınasgury it is idle to doubt that I overlooked the statement in question 
(which was in fact consulted before writing the passage now criticised), 
I did not further include him amongst the older writers, nor do I be- 
lieve that careful and philosophic writer to have been guilty of error. 
Until Jomsstoxe’s full memoir appears it would be premature to com- 
