200 JOHN BEARD. 



to homologise the two structures, and the folding could be more easily 

 explained as brought about by the mere physiological need of increased 

 surface. But surely it is a great change from a respiratory structure 

 and function to a sensory structure and function ; a change which, in 

 spite of the basis of truth in Dohrn's law of change of function, has 

 not, so far as I am aware, been shown to have occurred in any 

 other case. True, Dohrn 1 has recognised a gill-cleft in the hypophysis, 

 but he has declined to ascribe a sensory function to that structure. 



Froriep, 2 also, in discussing my views as to the nature of the 

 Vertebrate auditory organ, has suggested that the ear is really a 

 a modi6ed gill-cleft. But, as I shall presently show, this suggestion 

 cannot be accepted, or even be held with any amount of reserve, for it 

 is based on erroneous ideas of the primitive nature of the dorsal roots 

 of cranial nerves. 



If my discoveries stood alone, I should conceive it as highly 

 probable, if not certain, that the nose is really a branchial sense organ. 

 But this view of its nature is confirmed in a most striking manner, 

 and rendered as certain as anything can possibly be by the researches 

 of Blaue. 3 



These researches have been carried out on a considerable series of 

 fish and Amphibians, and have led to the conclusion that in the lowest 

 form of adult nose met with, viz. the nose of some fishes and Amphi- 

 bians (Belone, the herring, and Proteus), the structure of the nasal 

 membrane is essentially made up of a series of "smell buds" (Riech- 

 knospen), and between these an indifferent stratified epithelium. 

 These smell buds are identical in structure with the so-called taste- 

 buds of the papilla foliata of the tongue, say of a rabbit, and are also 



identical with the structures in the skin of fishes, which are here called 



branchial sense organs, and which are usually known as sense organs 



of the lateral line. 



In the common Triton those structures described by Blaue are 



readily found in transverse sections passing through the nasal cavities. 



One such section is figured in outline in fig. 48, and a part of the 



section, showing two sense bulbs of the nose, or smell buds, is figured 



under high magnifying power in fig. 49. 



1 Dohrn, " Studien, &c," No. 2, ' Mittheil. a. d. Zool. Stat, zu Neapel,' Bd. iii. 



2 Froriep, "Ueber Anlagen von Sinnesorganen am Facialis," 'Archiv fiir Anat. und 

 Physiol.,' 1885. 



3 Blaue, "Ueber Bau der Nasenschleimhaut bei Fischen und Amphibien," 'Archiv fiir 

 Anat. und Physiol.,' 1884. 



