152 



VERTEBRATE ZOOLOGY 



fied spine of the dorsal fin on top of the head looks like a trigger 

 and gives them their name. The FUe-Fishes or Fool-Fishes (Fig. 92) 

 are still more flatly compressed and the scales are reduced to vesti- 

 gial structures; the small mouth with its protruding teeth and the 

 funny staring expression of the eyes have given them an uncompli- 

 mentary name. The Trank-Fishes (Fig. 93) are big-headed fishes in- 

 closed in a heavy immovaljle armor, composed of closely imited 

 plates, with a large posterior opening that allows the curious httle 

 tail to waggle, and smaller openings for the pectoral, dorsal, and anal 

 fins. Puffers or Globe-Fishes are unarmored forms, shaped, when de- 



FiG. 93. — Hawaiian Trunk-Fish, Ostrachion schlemmeri. (Redrawn after Jordan 

 and Evermann.) 



flated, much like Trunk-Fishes, l.)ut capable of blowing thenrselves up 

 with water to several times their normal dimensions, thus making 

 themselves difficult to swallow. If taken out of water these strange 

 little fellows suck in air till thej^ are of a dnuu-like tightness. Some of 

 the Globe-Fishes are said to be extremf>ly poisonous. The Porcupine- 

 Fishes are shaped much like the Puffers in a deflated or partly de- 

 flated condition, some being much rounder than others; but they are 

 covered with a heavy spiky armor that has suggested their name. 

 They also have the reputation of being decidedly poisonous. The 

 Head-Fishes or Sun-Fishes (Fig. 94) represent tlic climax of relati\'e 

 increase of head over body, a character exhibited by the whole group; 

 they are little more than animated fish heads. The bod\' is so abbre- 

 viated that the dorsal and anal fins ai:)pear to be attachetl to the upper 

 and lower parts of the head. They inlui.lnt the tropical and sub-tropi- 

 cal seas, living a sluggish, floating life that is almost sedentary. Large 



