CHAEACINID^. 609 



broader behind than in front ; the hinder series is composed 

 of two conical teeth. All the teeth are strong, few in number. 



Fourteen species from Tropical Africa; several inhabit 

 the Nile, of which the "Eaches" (A. dentex and A. kotschyi) 

 are the most common. 



Tetragonopterus. — The dorsal fin is placed in the middle of 

 the length of the body, above or immediately behind the ventrals ; 

 anal fin long. Body oblong or elevated, covered with scales of 

 moderate size ; belly rounded. Cleft of the mouth of moderate 

 width. Anterior teeth strong, lateral teeth small. Intermaxil- 

 lary and mandibulary teeth sub-equal in size, with a compressed 

 and notched crown, the former in a double, the latter in a single 

 series ; maxillary with a few teeth near its articulation, rarely 

 with the entire edge denticulated. 



Of all the genera of tliis family Tetragonopterus is repre- 

 sented by the greatest number of species ; about fifty are 

 known. Some of them seem to have a very wide range, 

 whilst others are merely local. All are of small size, rarely 

 exceeding a length of eight inches. 



Chirodon. — Dorsal fin placed in the middle of the length of 

 the body, behind the ventrals ; anal long or of moderate length. 

 Body oblong, covered with scales of moderate size ; lateral line 

 not continued to the tail. Belly rounded before the ventrals. 

 Cleft of the mouth narrow, maxillary short. A single series of 

 small serrated teeth in the intermaxillary and mandibulary ; 

 maxillary teeth none. 



7. — Cliirocloii albiirniis. 



Three species of small size from various parts of South 

 America; the species figured is represented of the natural 

 size, and comes from the Upper Amazons. 



2e 



