1909.] OLFACTORY ORGAN OF TELEOSTBAN FISHES. 611 



above the termination of the olfactory nerve, such variation as 

 occurs being mainly confined to details of the nostrils. 



Although this impression is no doubt in part due to the natural 

 tendency of text-books to lay too great stress upon the condition 

 found in the usual teaching type which in this case is generally 

 a Gadid, a study of the original papers dealing with this particular 

 organ shows that the work done upon it has been neither large 

 in amovmt nor particularly extensive in scope. 



The following is, I think, a fair statement of the present state 

 of our knowledge of the coarse anatomy of the Teleostean JSTose, 

 and of the chief sources from which it is derived : — 



Owen * and Milne-Edwards f mention that in the Mackerel 

 and Anarrhichas there are certain accessory nasal sacs 

 in connection with the true olfactory chamber which 

 act as comjjressible reservoirs by means of which, as 

 in the case of the pituitary csecum of the Lamprey, a 

 current of water is driven through the olfactory 

 chamber by the movements of the jaws and opercula in 

 respiration. 

 1876. Sophie Pereyaslawzefi' t published a preliminary paper on 

 the olfactory organ of Fishes, and in it described in 

 detail the coarse and fine anatomy of Solea impa?' and 

 Lophius jnscatorius. The full paper seems never to 

 have appeared — a matter for regret, for from the list 

 of genera and species mentioned in the preliminary 

 paper as the material upon which the work was done, 

 it would evidently have been a valuable contribution to 

 the subject. 

 1884. Blaue § in a most important paper on the olfactory mem- 

 brane in Fishes and Amphibia gives short descriptions 

 of the coarse anatomy of the olfactory pit and rosette 

 in several species of Teleostei. The descriptions so far 

 as they go are good, but as they are incidental to the 

 true subject of the paper and only deal with the anatomy 

 so far as it is necessary for the purpose in hand, they 

 are naturally imperfect. However, in this paper thei-e 

 is a certain amount of information upon the form of the 

 olfactory chamber and rosette in Belone, Exoccetus, 

 Trigla, Esox, Umbra, Coitus, Gohius, Gadtis. 

 1887. Wiedersheim H writes a full and interesting account of a 

 series of stages in the degeneration of the olfactory 

 oi"gan of Plectognaths, tracing its ti'ansformation from 

 a simple concavity of the normal type to the condition 

 of a split tentacle in which the olfactoiy membrane is 

 fully exposed. The species described are Tetrodon 



* Anat. Vertebrates, vol. i. p. 329. 



f Leijons sur la Physiol. T. xi. 1874, p. 475. 



X Inaug.-dissert. Ziiricli. 1876. 



§ Arch. f. Anat. 1884, p. 241. 



II Festschrift v. Kolliker, 1887, p. 73. 



42* 



