226 THE OEGAN OF SMELL. 



found in the head of the fish, and which must be 

 known to every investigator of the gastronomical 

 merits of his game, form part of the mechanical 

 apparatus of hearing. 



The external or mechanical apparatus of the 

 organ of smell is a pair of small cavities or cham- 

 bers, communicating with the aqueous element 

 by means of four apertures, and situated near the 

 extremity of the snout. The two openings of 

 each olfactory chamber are intended to permit a 

 free ingress and egress to the water in which the 

 odorant principles are dissolved. But there exists 

 no contrivance, so far as we know, for maintain- 

 ing a constant current through the chambers. 

 In this particular, the organ of smell of fishes is 

 greatly inferior to that of higher animals; for in 

 the latter, the olfactory chambers give passage to 

 the greater part of the air which enters the lungs, 

 and are thus enabled to test the quality of all 

 the air received into the chest for respiration. 

 In fishes this power is less requisite, hence the 

 inferiority of construction. The olfactory cham- 

 bers are lined by a soft membrane, technically a 

 mucous membrane, which is richly supplied with 

 blood-vessels, and is brought into connection with 

 the vital organ by means of a moderately large 

 conducting nerve. The arrangement of this 

 membrane evinces one of those beautiful con- 

 trivances which are so frequently met with in the 



