76 INTRODUCTION. 



nostrils, in general, appear externally like a 

 double hole or opening, and the branches of the 

 nerve are ramified on a sort of cushion at the 

 bottom, or upon the side. The cut will shew 



the great proportion of nerve supplied from the 

 brain to the nostrils. In a few, they are like 

 prolonged tubes, as among the eels, where the 

 multiplicity of nervous filaments is very great ; 

 and in one fish they are remarkable as being 

 placed on a sort of stalk like a mushroom, in 

 which the openings are placed with the nervous 

 distribution. Seeing, then, a certain extent of 

 development, we cannot doubt that impressions 

 of smell are conveyed. In proof, various per- 

 fumes are successfully used by anglers to attract 

 the fishes. Eels are led into traps by baits placed 

 within, which they could only discover by smell ; 



appear to have a finer sense of hearing than of sight. 

 When seen upon the coast, they would allow themselves to 

 be approached, so long as silence was preserved, but on 

 speaking, fled immediately. 



