162 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 
plood is said to attract at once thousands of these fishes to the 
spot.” 
Two families of Heterognatht are recognized: the Erythri- 
nide, which lack the adipose fin, and the Characide, in which 
this fin is developed. The Erythrinide 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 Characide, 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.—Brycon dentexr Giinther. Family Characide. Nicaragua. 
very diminutive fishes, Hydrocyon exceedingly voracious ones, 
reaching a length of four feet, with savage teeth. Many of the 
species are allies of Tetragonopterus, 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 Eventognathi (ev, well; éy, within; 
yvaoos, jaw) are characterized by the absence of teeth in the 
jaws and by the high degree of specialization of the lower phar- 
