776 Dr- 'f- BEARD, 



of their primitive nature, for all zoologists hold the Teleostei to be 

 derivatives of Ganoids, and the Ganoids have certainly not been evol- 

 ved from any fishes like existing Selachians. 



Further, if the undivided condition of the olfactory epithelium (a 

 condition the actual existence of which is not certain, for possibly 

 everywhere the ultimate structure of that epithelium has the form of 

 buds) is the primitive one, then an argument supporting that view 

 can be just as well applied to the sense organs of the lateral line. 

 But, if any morphologist will venture to assert that a linear streak of 

 sensory epithelium, reaching from the vagus region to the posterior 

 end of the tail, was the original condition of the lateral line, he will 

 find himself stranded in a whole sea of troubles and contradictions. 



Emery remarks (50, p. 590) „falls die BLAUE'sche Ansicht richtig 

 wäre, so sollten in der Ontogenie solcher Fische, welche im erwach- 

 senen Zustand keine Riechknospen haben, solche Knospen oder doch 

 Spuren davon während der Jugend auftreten etc." 



The necessity is not obvious. The lateral line, (in the ontogeny 

 wohl bemerkt), is at first undivided into sense buds, and why may not 

 that also happen , and even remain permanently , in the case of the 

 nose, without prejudice to the morphological nature of the „Riech- 

 knospen", if they do appear ?. 



If they do not become diflerentiated, then the nose epithelium re- 

 mains in a more embryonic condition (so to speak). How does Prof. 

 Emery know that smell-buds are not always present in the nose 

 in a disguised form? The facts recorded here for Jacobson's organ 

 — a part of the nose! — should be taken to heart, for were it not 

 for the development of the smell-bud ganglia it would hardly be 

 possible to recognise the smell-buds themselves, but they would be 

 present none the less ! 



The questions here touched upon and the answer to Prof. Gegen- 

 baur's argument regarding the nose and the branchial or lateral sense 

 organs themselves could be best discussed after the publication of my 

 further researches on these sense organs; this publication is all the 

 more necessary as in my opinion the facts of development are very 

 clear. Much of the morphology of the lateral line can be made out, 

 and the phylogenetic origin of the sense organs appears to me to be 

 now obvious. What the facts and probabilities are we shall see 

 in the memoir which follows this. Here only the remark that Prof. 

 Dohrn's recent statement (40, p. 452), that the lateral nerve grows 

 from the ganglion to the peripheral sense organs just like an ordinary 



