80 COMMERSONIAN TRIPLE-TAIL. 



which it represents a continuation or appendix, 

 and even seems to form a part : the dorsal fin is in 

 the same manner a kind of auxiliary to the tail- 

 fin : it is formed of an equal number of rays with 

 the vent-fin, but is situated at a greater distance- 

 from the head, and is a third part longer, stretch- 

 ing backwards, not only as far as the tail, but be- 

 yond it ; and as these two fins, viz. the dorsal and 

 anal, reach that of the tail, it follows that the latter, 

 at first view, appears as if composed of three dis- 

 tinct parts, and hence the name of Triurus, or 

 Triple-Tail, applied to this fish by Commerson. In 

 the mean time the real tail is so short that it appears 

 more like a defective than a finished part, and is 

 fringed at the edge by the terminations of the nu- 

 merous, soft, divided rays of which it is composed. 

 The colour of this fish is a brownish red, changing 

 into silvery beneath the head, and into flesh-colour 

 on the sides, belly, and tail, while a spot of clear 

 white appears beyond the base of the pectoral fins. 

 This curious genus was discovered by Commerson 

 in the stomach of a species of Scomber ; five indi- 

 viduals, perfectly uninjured by the action of the 

 stomach, being taken out : several others were af- 

 terwards observed, sporting on the surface of the 

 sea. In some points this fish seems to bear a near 

 alliance to the genus Centriscus. 



