1914.] NATURAL SCIENCES OF PHILADELPHIA. 251 



below 1. 1. to ventral origin, and 3 to anal origin; predorsal scales 

 14, counted forward to hind end of occipital process; snout 4 in 

 head, measured from upper jaw tip; eye 3f; maxillary 3; inter- 

 orbital 3; gill-rakers 16 + 34; length 143 mm. This example 

 differs slightly from others in the collection I previously studied 

 in the slightly curved dorsal profile. Compared with the type of 

 Triportheus flavus Cope, it shows few scales above 1. 1., and shorter 

 pectoral, this not reaching tip of ventral, or scarcely beyond dorsal 



origin. 



SERRASALMIN.E. 



Serrasalmus gymnogenys Gunther. 



One example 130 mm. 



Serrasalmus rhombeus (Linnaeus). 

 One example 148 mm. 



Pygocentrus piraya (Cuvier). 



One example 158 mm. 

 Pygocentrus scapularis (Gunther). 



One example 160 mm. 

 Pygopristis denticulatus (Cuvier). 



Two examples, 85 and 112 mm. Each show about twelve darker 

 vertical streaks on side of back, though last two which are on caudal 

 peduncle anteriorly and on caudal base larger and darker. Upper 

 sides also with a number of small dark brown spots, obscure and 

 rather irregular. Both specimens infested with psorosperms^ 

 especially smaller. 



MYLIN^. 



Catoprion mento (Cuvier). 



Two examples, 90 to 135 mm. 



Mylophus rubripinnis (Muller and Troschel). 



Two examples, 105 to 175 mm. 



CYNODONTIN.E. 



Cynodon gibbus Spix. 



One example 220 mm. 



CHARACIN.E. 



Exodon paradoxus Miiller and Troschel. 



Two examples, 98 and 118 mm. 



XIPHOCHARAX gen. nov. 

 Type Xiphocharax ogilviei sp. nov. 

 Premaxillary with pair of small approximated or median canines, 

 two smaller canines at distal end of each bone, and all smaller teeth 



