202 JOHN BEARD. 



But though he is convinced of this homology, he nowhere hints that 

 the nose is to be regarded as a specialised portion of the so-called 

 organs of the lateral line, and in fact accepts and supports Marshall's 

 gill theory of the nature of the nose, and derives his smell buds from 

 skin sense bulbs which, originally present on the nasal visceral arch, 

 as in other cases, have wandered into the nasal-cleft. 



Now, although sense bulbs are present on and along the visceral 

 arches of many fishes, they are not primitively there, their primitive 

 position being above the cleft, not along it. Their presence along the 

 arch is a later development. This fact and the facts of development 

 as given before are entirely opposed to Blaue's supposition. 



It is a curious commentary on the influence of the same set of facts 

 on the views of different zoologists, that while Blaue, as the result of 

 his researches, advocates the gill nature of the nose, Prof. Wieders- 

 heim, as he has kindly informed me by letter, since reading Blaue's 

 paper, considers it necessary, as most morphologists would, to give up 

 entirely the notion that the nose is a gill-cleft. 



My own opinion does not rest on the researches of Blaue alone. 

 Apart from those discoveries, I should believe myself justified in hold- 

 ing, as against the views of Prof. Dohrn and of my own teacher, Prof. 

 Marshall, that the nose is the modified sense organ of a gill-cleft 

 rather than a gill-cleft itself. 



But though maintaining that Blaue's results are not necessary to 

 support this view, yet, blending together those results and the facts 

 recorded in this paper as to the development, &c, of the supra-branchial 

 sense organs and of the nose itself, I believe that my view of the 

 nature of the nose has so solid a foundation in facts that even the 

 most sceptical zoologist can have little hesitation in accepting it. 



Shortly stated, the olfactory organ is a branchial sense organ, and 

 the olfactory nerve is a segmental nerve, the post-branchial and prae- 

 branchial branches of which, in consequence of the absence of a nasal- 

 cleft, are not developed. In fact, the olfactory nerve is the sensory 

 remnant of the most anterior segmental nerve. 



Development op the Nose in Amphibia and Teleostei. 



Hoffmann has described the development in Salmo, but has not 



ascribed an epiblastic origin to the nerve ; this, however, is the case 



in both Teleostei and Amphibians. In Amphibia, Gotte held that 



the olfactory nerve was developed in mesoblast. In fig. 4. the develop- 



