1 62 Series Ostariophysi 



these fish are called), and torn to pieces before it can be with- 

 drawn from the water. The caribes themselves are rarely 

 hooked, as they snap the hook or cut the line. The smell of 

 blood is said to attract at once thousands of these fishes to the 

 spot." . 



Two families of Heterognathi are recognized: the Erythri- 

 nida, which lack the adipose fin, and the Characida, in which 

 this fin is developed. The Erythrinidce are large pike-like 

 fishes of the South American rivers, robust and tenacious of 

 life, with large mouths armed with strong unequal teeth. The 

 best-known species is the Trahira (Hoplias malabaricus) . 



Among the Characidcs, Serrasalmo has been already noticed. 

 Citharinus in Africa has very few teeth, and Curimatus in South 

 America none at all. Nannocharax in Africa is composed of 



FIG. 121. Bryc&n dentcx Giinther. Family Charatidce. Nicaragua. 



very diminutive fishes, Hydrocyon exceedingly voracious ones, 

 reaching a length of four feet, with savage teeth. Many of the 

 species are allies of Tetragonopterns, small, silvery, bream-like 

 fishes with flat bodies and serrated incisor teeth. Most of these 

 are American. A related genus is Brycon, found in the streams 

 about the Isthmus of Panama. 



Extinct Characins are very rare. Two species from the Ter- 

 tiary lignite of Sao Paulo, Brazil, have been referred to Tetra- 

 gonopterus T. avus and T. ligniticus. 



The Eventognathi. The Eventognaihi (ev, well; ev, within; 

 yvados, jaw) are characterized by the absence of teeth in the 

 jaws and by the high degree of specialization of the lower phar- 



