Soutk-Ameruaii Characid FtsLes. 389 



Diameter of eye 4 in length of head, iiiterorbital width 21. 

 18 or 19 scales from upper angle of gill opening to base of 

 caudal fin, 33 or 34: in the lateral line. Dorsal 12; origin 

 above base of jxdvics, equidistant from tip of snout and end 

 of scales on caudal. Anal 11. 

 Upper Amazon. 



1. 170 mm. R. Cupai. Stevens. 



Cope's type was a specimen of 65 mm. with the head I of 

 the lengtli, eye | and interoibital width | of the length of 

 head, &c. He described the outer prsemaxiihny teetli as 

 conical, and indeed they are less expanded than in 0. macro- 

 /e/)idotus, but they have a pair of cus[is. 



2. Pykkhulina. 



Pyrrhulina, Cuv. & Val. Hist. Nat. Poiss. xix. 1846, p. 535 ; Gunth. 

 Cat. Fish. V. p. 286 (1861). 



Bod}' oblong or rather elongate, compressed. Scales 

 large ; no lateral line. Mouth moderate or sn)all, terminal, 

 with the lower jaw projecting ; praemaxillary and mandibulary 

 teeth conical, biserial ; palate toothless. Nostrils close 

 together. Gill-membianes free. Dorsal and anal fins short; 

 no adipose fin. 



Synopsis of the Species. 



I. 26 or 27 scales in a longitudinal series ; diameter of eye 2§ to 3^ in 



length of bead, in specimens of 35 to 80 mm.. . 1. jilamentosa. 



II. 20 to 25 scales in a lougitudLnal series ; diameter of eye 3 to 4 in 



length of head, in specimens of 25 to 85 mm. 



A. Body slender, the depth 5 in the length ; caudal peduncle nearly 



as long as head ; 22 scales in a longitudinal series. 



2. nattereri. 



B. Body deeper, the depth 3| to 4^ in the length. 



1. Caudal peduncle at least § length of head ; 22 to 25 scales in a 



lougiiudiual series 3, semifasciata. 



2. Caudal peduncle at most f length of head, 

 laterorbital width 2 in length of head ; 20 scales in a 



longitudinal series; depth of body 3i in length . . 4. vittata. 

 Interorbital width 2 to 2^ in length of head ; 20 to 23 



scales in a longitudinal series ; depth of body 3| 



to 4^ in length 5. australis, 



Interorbitiil width 2A to 3 in length of head ; 20 to 



22 scales in a longitudinal series 6. hrevis, 



1. PyrrhuUna Jilamentosa. 



Pyrrhulina Jllamentosa, Cuv. & Val. Hist. Nat. Poiss. xix. 1846, p. 535, 

 pi. 589; Giinth. Cat. Fish. v. p. 286 (1864). 



