120 . FISHES. 



Organs of Touch. — The faculty of touch is more developed 

 than that of taste, and there are numerous fishes which possess 

 special organs of touch. Most fishes are very sensitive to 

 external touch, although their body may be protected by hard 

 horny scales. They perceive impressions even on those parts 

 which are covered by osseous scutes, in the same manner as 

 a tortoise perceives the slightest touch of its carapace. The 

 seat of the greatest sensitiveness, however, appears to be the 

 snout and the labial folds surroundiug the mouth. Many 

 species possess soft and delicate appendages, called barbels, 

 which are almost constantly in action, and clearly used as 

 organs of touch. Among the Triglidce and allied families, 

 there are many species which have one or more rays of the 

 pectoral fin detached from the membrane, and supplied with 

 strong nerves. Such detached rays (also found in the Poly- 

 nemidcB, Bathypterois) are used partly for locomotion, partly 

 for the purpose of exploring the ground over which the fish 

 moves. 



Some fish appear to be much less sensitive than others, or 

 at least lose their sensitiveness under pecuhar circumstances. 

 It is well known that a Pike, whose mouth has been lacerated 

 and torn by the hook, continues to yield to the temptation 

 of a bait immediately afterwards. The Greenland Shark 

 when feeding on the carcase of a whale allows itself to be 

 repeatedly stabbed in the head without abandoning its prey. 

 A pair of Congers are so dead to external impression at the 

 time of copulation, and so automatically, as it were, engaged, 

 that they have been taken by the hand together out of the 

 water. 



