

SENSE OF SMELL IN FISHES. 69 



superior face, and even occasionally, as in skates 

 and sharks, on its under surface, near the angle of 

 the mouth. In the lamprey, they are approxi- 

 mate on the upper part of the head,- opening by 

 one common orifice. In the great majority of fishes, 

 perhaps in all the osseous kinds, each nostril opens 

 by two orifices, the one posterior to the other, and 

 in some cases at a considerable distance. These 

 are what are called double nostrils an inaccurate 

 term, in as far as each pair of holes leads only to a 

 single cavity. The margins of the anterior orifice 

 are often tubular, as in the eel ; and sometimes a 

 single side of the tubular margin is prolonged into 

 a tentacular appendage, as in several Siluri. In 

 the genus Lophius, the nostrils are borne upon 

 a little pedicle, so as somewhat to resemble certain 

 fungi. It does not appear that the envelope 

 of the nostrils, at least in the osseous fishes, 

 possesses mobility, or that the orifices are furnished 

 with muscles, by means of which they can be open- 

 ed and shut. It is certain, however, that fishes 

 possess the faculty of perceiving odours ; that vari- 

 ous scents attract or repel them ; and there is no 

 reason to doubt that the seat of that perception lies 

 in the nostrils. It may also be reasonably conjec- 

 tured that its strength depends mainly on the de- 

 gree of development produced by the number and 

 extent of the interior folds. Mr. Yarrell presumes 

 the sense of smell to be acute, from the selection 

 fishes make while searching for their food, and the 

 advantage (not much that we know of) gained by 

 anglers from the use of scented oils. " A pike," 



