24. BKTCON. 333 



23. CHALCEUS. 

 Chalceus, Cuv. Mim. Mus. iv. p. 454. 



The dorsal fin is. placed behind the middle of the length of the 

 body, behind the ventrals ; anal short. Body oblong, covered with 

 large scales unequal in size. Belly rounded. Cleft of the mouth of 

 moderate width. Maxillary teeth very small ; intermaxillary and 

 mandibulary teeth of moderate size, tricuspid, the former in a triple, 

 the latter in a double series ; the hinder series of the lower jaw is 

 formed by a pair of conical median teeth and by small lateral teeth. 

 Nostrils close together, separated by a valve only. Gill-opening wide, 

 the gill-membranes being free from the isthmus and separate. 



Guianas, Brazil. 



1. Chalceus macrolepidotus. 



Chalceus macrolepidotus, Cuv. Mem, Mus. iv. p. 454. pi. 21. fig. 1 ; 



Cuv. $ Vol. xxii. p. 240. 

 Brycon macrolepidotus, Mull. Sf Trosch. Hor. Ichth. i. p. 15. 

 Chalceus ararapeera, Cuv. fy Vol. xxii. p. 244. 



D. 12. A. 12. V. 9. L. transv. 3/3. 



The dorsal fin commences immediately behind the root of the ven- 

 tral. Twenty-one transverse series of scales above, and thirty-five 

 scales in the lateral line. Fins red. 



Guianas, Brazil. 



a. Fine specimen. Essequibo River. From Mr. Ehrhardt's Collection. 

 b-c. Adult. British Guiana. Presented by Sir B. Schomburgk. 

 d. Adult. River Cupai. Purchased of Mr. Stevens. 



24. BRYCON* 



Brycon, sp\, Mull. 8f Trosch. Hor. Ichth. i. p. 15. 



Dorsal fin placed in the middle of the length of the body, behind 

 the ventrals ; anal long. Body oblong, covered with scales equal in 

 size. Belly rounded in front of the ventrals, and compressed behind 

 them. Cleft of the mouth rather wide. Intermaxillary with three 

 series of notched or tricuspid teeth, the middle series being irregular ; 

 edge of the maxillary with small teeth ; mandible with a series of 

 strong tricuspid teeth, and with a pair of conical teeth in the middle 



* 1 . Brycon schomburgkii, Mull. $ Trosch. Hor. Ichth. i. p. 29. taf. 6. fig. 2. — 

 D. 11. A. 26. Scales of moderate size. The height of the body is 

 nearly equal to the length of the head, and somewhat less than one- 

 third of the total (without caudal). The lateral portion of the inner 

 series of mandibulary teeth extends forwards to the front teeth. The 

 origin of the dorsal fin is behind the root of the ventral, in the middle 

 between the extremity of the snout and the root of the caudal. Lateral 

 line distinct through its entire course. The pectoral extends to the 

 ventral. Coloration uniform, without spots. — Essequibo River. 



2. Chalceus orbignyanus, Cuv. Sf Vol. xxii. p. 249 ; Kner, Denkschr. Acad. 



Wiss. Wien, 1860, xviii. p. 11. — Rio de la Plata, Rio Gruapor<§. 



3. rodopterus, Cuv. $ Vol. xxii. p. 249. — Buenos Ayres. 



4. devillei, Casteln. Anim. Amer. Sud, Poiss. p. 69. pi. 36. fig. 2. — Bahia. 



