FISHES OF THE GULF OF MAINE 293 



THE TRIGGERFISHES. FAMILY BALISTID^ 



The triggerfishes are very divergent from the ordinary spiny-rayed fishes 

 anatomically, and then- external appearance is so characteristic that they are not 

 apt to be mistaken, unless for their close relatives, the filefishes (p. 294) . Their most 

 interesting external characteristics are that the first spine of the first dorsal fin is 

 very much stouter than the others and can be locked erect by the second, and that 

 the large bony scales form a hard armor. Other distinctive features are mentioned 

 below in the description of the Gulf of Maine species. Most of the triggerfishes 

 are purely tropical, and it is only casually that the family enters into the Gulf of 

 Maine fauna. Some of the tropical species are poisonous if eaten. 



109. Triggerfish {Balistes carolinensis Gmelin) 



Jordan and Evermann, 1896-1900, p. 1701. 



Description. — The readiest field marks of the triggerfish are its deep compressed 

 body and slender caudal peduncle; small terminal mouth with both dorsal and 



Fig. 134.— Triggerfish (Bahstes carolinensis) 



ventral profiles of the nose nearly straight; eye situated so high as to give its face 

 a very peculiar aspect; large projecting incisor teeth; and especially its unusually 

 stout first dorsal spine; very short gill openings wholly above the insertions of the 

 pectorals; and the plate armor of thick scales with which its entire head and body 

 are clad. The spinous dorsal fin is triangular, with three spines, the first so stout 

 that it is more like a horn, situated close behind the eye and with the second spine 

 acting as a trigger to lock the first erect, whence the common name of the fish. The 

 soft dorsal (27 rays), separated from the first by a considerable interspace, is rhom- 

 boid in outline, with the third or fourth rays longest, and tapers back to the base of 

 the caudal peduncle. The anal (25 rays) corresponds to the soft dorsal in outline 



