260 ZOOLOGY. 



bone of the belly (balista) short, but little developed. 

 Teeth, eight in each jaw. Rays of the first dorsal fin 

 2; second 24. Pectoral 14. Anal 21. Caudal 12. 



This may be the B. Maculatus, (Linn, and Gmel.,) or 

 Spotted File-fish, although it differs from that species, 

 as described by authors, in its colours, as well as in 

 having no prickles in the place of the ventral fin. We 

 met with many examples of this fish in the Pacific 

 Ocean, in lat. 16 N., long. 106 W. They were at- 

 tending a log of drift-wood, and came around the ship 

 in large shoals. The greater number were taken by 

 hook and line, and eaten by our crew. Their flesh, 

 though of coarse quality, proved to be wholesome; 

 notwithstanding the assertion of ichthyologists, that fish 

 of this genus are mostly poisonous. When first taken 

 from the water, this species, in common with its con- 

 geners, produces a loud grinding or gnashing sound 

 with its teeth. 



There is a remarkable peculiarity in the construction 

 of the anterior d orsal fin of the genus Balistes, and which 

 has obtained for this family the trivial name of " Trigger- 

 fish." When this fin is elevated, its first spinous ray, 

 which is exceedingly thick, remains fixed, and cannot 

 be depressed, with any degree of force short of that 

 which would fracture it, unless the second ray is de- 

 pressed, when the first immediately follows. The animal 

 mechanism which effects this is curious. A strong 

 trough-shaped bone, its concavity placed uppermost, 

 corresponds to the base of the anterior dorsal fin, and 

 gives it support. The inferior edge of its anterior or 

 broadest extremity is fixed to the head of the fish by a 

 bony peg, or condyle, received into a corresponding 

 circular orifice, and by its superior edge being con- 

 tinuous with the summit of the cranium; while its 



