FISHES. 



133 



head is naked, the body scaly. The structure of the fins is in general similar to that 

 seen in the Cyprinidee. 



No Characinidse are found in the Old World except in Africa. In America a very 

 few extend their range northward into Mexico and the southernmost of the West 

 Indies, and a single one ( Tetragonopterus argentatus) is abundant in southern Texas. 

 The family is divided by Dr. Gtinther into eleven sub-families, only the more impor- 

 tant of which need be mentioned here. 



The Erythrininae differ from the other Characins in having no adipose fin. The 

 species are all South American, and some of them are large fishes with very strong 



Fig. 87.— Serrasalmo piranya, caribe. 



teeth. The Curimatinae, likewise numerous in South America, have the teeth very 

 few or wanting, and the dorsal fin short. 



The Citharininse, with the teeth likewise very feeble, have the dorsal fin rather long. 

 The few species are African. The Anostominse have the teeth well developed, and 

 the gill membranes grown to the isthmus. They are mostly small fishes from Brazil 

 and Guiana. Allied to them are the very small Nannocharacinse from Africa. 



The largest of the sub-families is that of Tetragon op terinaa, distinguished by the 

 free gill membranes and the incisor-like teeth, which are notched or serrate on the edge. 

 The species are found both in South America and Africa. The largest genus is 

 Tetragonopterus, all the species of which are American. 



The Hydrocyoninse differ especially in having the teeth in the jaws conical and 

 very strong. They are voracious fishes, many of them of large size, found in the 

 rivers of Africa and South America. Some of them {Ilydrocyon, Cynodon) reach 



