24. BEYCON. 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 ; intermaxillaiy and 

 maudibulary 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. <5- Val. xxii. p. 240. 

 Erycon macrolepidotus. Mull. 8f Trosch. Hor. Ichth. i. p. 15. 

 Chalceus ararapeera, Cuv. 4'" Val. 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 scries 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. 

 h-c. Adult. British Guiana. Presented by Sir R. Schomburgk. 

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



24. BRYCON*. 



Brycon, sp., Miill. &,- 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 maxiUary with small teeth ; mandible with a seiies of 

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



* 1. Brycon schomburgkii, Miill. 4' Trosch. Hor. Ichth. i. p. 29. taf. 6. fig. 2. — 

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

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

 third of the total (w-ithout caudal). The lateral portion of the inner 

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

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

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

 line distinct tlu-ough its entire course. Tlie pectoral extends to the 

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



2. Chalceus orbignyanus, Cui\ ^- I'al. xxii. p. 249; Kiur. Dcnkschr. Acad. 



U'iss. Whn, 1860, xviii. p. 11.— Eio de la Plata, Rio Giiapore. 



3. rodopterus, Cuv. 4' V"l- '^xi'- P- 249. — Buenos Ayres. 



4. devillei, Casteln. Anim. Amir. Sud, Poiss. p. 09. pl. 3G. fig. 2. — Babia, 



