CHAPTER XII 

 ADAPTATIONS OF FISHES 



PINES of the Catfishes. The catfishes or horned pouts 

 (Silurida) have a strong spine in the pectoral fin, one 

 or both edges of this being jagged or serrated. This 

 spine fits into a peculiar joint and by means of a slight downward 

 or forward twist can be set immovably. It can then be broken 

 more easily than it can be depressed. A slight turn in the opposite 

 direction releases the joint, a fact known to the fish and readily 

 learned by the boy. The sharp spine inflicts a jagged wound. 



FIG. 133. Mad-torn, SchUbeodes furiosus Jordan and Meek. Showing the poisoned 

 pectoral spine. Family Siluridoe. Neuse River. 



Pelicans which have swallowed the catfish have been known to 

 die of the wounds inflicted by the fish's spine. When the catfish 

 was first introduced into the Sacramento, according to Mr. Will 

 S. Green, it caused the death of many of the native "Sacra- 

 mento perch" (Archoplites interruptus] . This perch (or rather 

 bass) fed on the young catfish, and the latter erecting their 

 pectoral spines in turn caused the death of the perch by tear- 

 ing the walls of its stomach. In like manner the sharp dorsal 

 and ventral spines of the sticklebacks have been known to cause 

 the death of fishes who swallow them, and even of ducks. In 

 Puget Sound the stickleback is often known as salmon-killer. 



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