,CHAP. V. DEFENCES OP FISH. 149 



sword of this fish driven completely through, is now, 

 as Dr. Shaw asserts, or was, in the British Museum : 

 the fish was killed by the violence of the effort ; and the 

 vessel, in all probability, was saved from foundering, 

 by the fish not having power to withdraw its snout. 

 We are unacquainted with the manner in which the 

 saw-fish (Pristis Antiquorum) uses the formidable ap- 

 paratus which terminates its snout ; but when we con- 

 sider that this part, in itself, is often no less than five feet 

 long, and that it is armed with from eighteen to twenty- 

 four strong spines on each side, it may be concluded to 

 be a deadly weapon. The electric quality possessed by 

 the torpedo is, no doubt, one of the means employed by 

 nature for effecting self-preservation : it is unknown, 

 however, against what particular enemies this unusual 

 defence is directed. 



(168.) Michaux is the only writer who has informed 

 us of the precise manner in 

 which the formidable spines 

 (fid- 49.) so general in the 

 fins of the Silures, or cat-fish 

 (SiluridcB Sw.), are used. The 

 Ohio abounds with these fish, 

 which may be caught with a 

 hand line, sometimes weigh- 

 ing 100 pounds. The first ray of the dorsal is 

 formed of a very strong and sharp spine, which the 

 animal uses to kill others of a smaller size ; for this 

 purpose it gets beneath the fish it intends to attack, 

 and then, suddenly rising, wounds it repeatedly in the 

 belly. " We had opportunities," he adds, " of ob- 

 serving this circumstance twice in the course of our 

 navigation" down the Ohio.* 



(169.) The power of quitting its native element, to 

 take refuge in another, belongs to the whole genus of 

 Exocwtus, or flying-fish; and doubtless to many species 

 of Trigla, or gurnard, where the pectoral fins are 

 equally developed. The former swim in shoals ; and 



* Mich. Trav. p. 131. 



i. 3 



