1909.] OLFACTORY ORGAN OF TELEOSTEAN FISHES. 613 



probably to be found scattered about in monographs, dealing 

 with special genera. The only one, however, to which I am able 

 to refer is the detailed description of the olfactory organ of the 

 Plaice by Cole and Johnston *. 



Some few years ago when a Catalogue of the Sense-organs 

 in the Museum of the College of Surgeons was in preparation, 

 my attention was directed to this subject of the anatomy of the 

 Fish nose, and from the few dissections then made it soon became 

 apparent that variations upon the fundamental ground plan are 

 far more numerous and general than the ordinary sources of 

 information would lead one to suppose. Since then I have 

 collected notes upon this subject, as occasion offered, and in doing 

 so have kept four main objects in view : — 



(1) To see how far the fundamental part of the olfactory 



organ (a concavity in the face, containing an olfactory 

 rosette) is constant in its form and in its position relative 

 to the bones of the skull. 



(2) To see how far the variations observed accord in their 



occurrence with authoritative systems of classification and 

 so are to be regarded as of taxouomic importance. 



(3) To explain so far as possible the action of such variations 



of structure as appear to be of functional importance. 



(4) To see if any connection can be traced between variations 



in the nose and the general habits of the Fish. 



The Fishes dissected belong to 32 families and 51 genera, 

 representing to some degree most of the larger divisions of the 

 order. They are mostly the common Fishes of the market, 

 supplemented by some exotic forms from the College stores, 

 for the identification of which I am much indebted to Mr. 

 Boulenger, F.R.S. In the following descriptions the Fishes have 

 been arranged in order according to Boulenger's system in the 

 Cambridge Natural History, with the exception of the Ana- 

 canthini which have been taken first, out of their proper place 

 in order that the simple unspecialised nose of the Haddock ma} 

 serve as a standard of comparison for the rest. 



A N A C A N T H I jSr I. 



Gadid^. 

 Gadus atglefinus (text-figs. 188 & 189). 



The nostrils (text-fig. 188, A, p. 614) lie in front of the orbit 

 in an area of soft skin bounded above by the nasal and frontal 

 bones and below by the lachrymal. A line passing through both 

 slopes from in front downwards and backwards at an angle of 

 about 45° to the horizontal. The anterior nostril is circular and 

 bordered by a low tubular lip elevated posteriorly to form a hood- 

 like flap, by which in forward progression water would be deflected 



* L. M. B. C. Memoiis, No. viii. Pleuronectes. 1901. 



