608 FISHES. 



the isthmus ; nasal openings remote from each other. Tropical 

 America. 



Leporinus. — Dorsal fin placed nearly in the middle of the 

 length of the body; anal short; ventrals below the dorsal. 

 Body oblong, covered with scales of moderate size ; belly rounded. 

 Cleft of the mouth small, with the lips well developed ; teeth 

 in the intermaxillary and mandible, few in number, flattened, 

 with the apex more or less truncated, and not serrated ; the 

 middle pair of teeth is the longest in both jaws ; palate toothless. 



This genus is generally distributed in the rivers east of 

 the Andes ; about twenty species are known, some of which, 

 like L. frederici, L. megalepis, are very common. They are 

 well marked by black bands or spots, and rarely grow to a 

 length of two feet, being generally much smaller. — The other 

 genera belonging to this group are Anastomus and Rhytiodus. 



V, Nannochaeacina. — A short dorsal and an adipose fin ; 

 teeth in both jaivs well developed ; notched incisors. The gill- 

 membranes are grown to the isthmus. Nostrils close together. 



One genus, Nannocharax, with two species only, from the 

 Nile and Gaboon ; very small. 



VI. Teteagonoptekina. — A short dorsal and an adipose 

 fim; the teeth in both jaws well developed, compressed, notched, 

 or denticidated ; the gill-membranes free from the isthmus, and 

 the nasal openings close together. South America and Tropical 

 Africa. 



Alestes.' — The dorsal fin is placed in the middle of the length 

 of the body, above or behind the ventrals ; anal fin rather long. 

 Body oblong, covered with scales of moderate or large size ; 

 belly rounded. Cleft of the mouth rather small. Maxillary 

 teeth none ; intermaxillary teeth in two series ; those of the 

 front series more or less compressed, more or less distinctly 

 tricuspid; the teeth of the hinder series are broad, molar-like, 

 each armed with several pointed tubercles. Teeth in the lower 

 jaw in two series ; those in the front series laterally compressed, 



