abstracts: ichthyology 295 



ICHTHYOLOGY. — The sense of smell in fishes. G. H. Parker and 

 R. E. Sheldon. Bulletin of the Bureau of Fisheries, 32:33-^6. 

 1912. Issued May 3, 1913. 

 The common beUef that fishes have a sense of smell has been hitherto 

 without the support of physiological evidence. In this paper are 

 recorded the results of experiments with three common species of fishes 

 which show reactions undoubtedly dependent upon the olfactory appa- 

 ratus. 



1 . A current of water passes thru the nasal chambers of many fishes in 

 a direction from anterior to posterior. It may be produced by ciliary 

 action (Ameiurus), by pressure due to the action of the respiratory mus- 

 cles (Fundulus) , or it may be a part of the true respiratory current 

 (Mustelus) . 



2. By means of this current dissolved substances in the water are 

 brought into contact with the olfactory surfaces. 



3. Fishes distinguish packets containing hidden food from similar 

 packets without food. 



4. This power of distinguishing the two classes of packets is lost when 

 the olfactory tracts are cut, when the anterior olfactory apertures are 

 stitched up or when the apertures are plugged with cotton wool. It is 

 revived on reopening the apertures by taking out the stiches or removing 

 the cotton wool. 



5. Mustelus and Ameiurus discover their food chiefly thru the ol- 

 factory sense ; Fundulus uses the eyes in addition to the olfactory organs 

 for this purpose. 



6. Mustelus, Fundulus, and Ameiurus use the olfactory organs to scent 

 food much as land animals do; these organs are true organs of smell, 

 i.e., distance receptors for the chemical sense. G. H. P. and R. E. S. 



