THE SENSE OF SMELL IN SELACHIANS 61 



V. SUMMARY 



1. A current of water, caused by respiratory movements, and 

 augmented by the forward motion of the fish in swimming, courses 

 through the nasal capsules of the dogfish. 



2. By this means substances in solution in the water come in 

 contact with the olfactory mucous membrane. 



3. Dogfish recognize and determine the location of food sub- 

 stances through a chemical sense. 



4. This power is lost when the olfactory capsules are filled with 

 loose cotton. It is regained when the cotton is removed. 



5. The plugging of one nostril only does not seriously affect 

 this power. 



6. The dogfish obtains its food almost, if not entirely, through 

 the sense of smell. 



7. The Selachians possess a true sense of smell, comparable 

 to that of the terrestrial vertebrates. 



Anatomical Laboratories, The University of Pittsburgh Medical School. 



