28o Field Museum of Natural History — Zoology, Vol. X. 



on side; maxillary with a few or no teeth; gill-rakers setiform; lateral 

 line complete; no predorsal spine; caudal naked. 



KEY TO THE SPECIES. 



a. Sides with a dark, plumbeous, lateral band, darkest and most 



distinct posteriorly, sometimes indistinctly visible on caudal fin; 



no caudal spot. Reaching a length of 150 mm. fasciatus, p. 280. 



aa. Sides with a plumbeous, lateral band, ending in a large, well 



defined, oval caudal spot. Reaching a length of no mm. 



ruberrimus, p. 281. 

 29. Astyanax fasciatus (Cuvier). 



Chalceus fasciatus Cuvier, Mem. Mus. Paris, V, 1819, 352 (Brazil). 

 Tetragonopterus fasciatus Cuvier & Valenciennes, Hist. Nat. Poiss., XX, 

 1848, 149 (Rio San Francisco); Gunther, Cat. Fish. Brit. Mus., V, 

 1864, 322 (Brazil; ? West Ecuador; ? Rio Chisay; ? Mexico; Guate- 

 mala) ; Vaillant, Bull. Mus. d'Hist. Nat. Paris, 1897, 221 (? Chagres). 

 Tetragonopterus fischeri Steindachner, Denkschr. K. Ak. Wiss. Wien, 



XLI, 1879, 166, PI. I, figs. I & 2 (Rio Mamoni, Panama). 

 Tetragonopterus panamensis (non Gunther) Steindachner, Denkschr. 

 K. Ak. Wiss. Wien, XLI, 1879, 166, PI. I, figs, i & 2 (Rio Mamoni, 

 Panama). 

 Astyanax fasciatus Fowler, Proc. Ac. Nat. Sci. Phila., 1906, 346 (Para). 

 Astyanax rutilus Eigenmann & Ogle, Proc. U. S. Nat. Mus., XXXHI, 



1907, 19 (Truando; West Coast of Central America). 

 Astyanax grandis Meek & Hildebrand, Field Mus. Nat. Hist. Pub., 

 Zool. Ser., X, 191 2, 67 (Rio Juan Diaz, Panama). 

 Head 3.55 to 4.35; depth 2.35 to 2.6; D. 10 or 11; A. 25 to 27; scales 

 36 to 39. 



Body deep, compressed; the back elevated; head small; snout coni- 

 cal, 3.7 to 4.4 in head; eye 2.6 to 3.6; interorbital 2.4 to 3; mouth small; 

 jaws subequal; maxillary to or sHghtly past anterior margin of eye, 

 slightly longer than snout; premaxillary teeth in 2 regular series, each 

 with 8 teeth; maxillary with 2 small teeth near its juncture with the 

 premaxillary; lower jaw with 8 strong teeth anteriorly and abruptly 

 smaller ones at sides; gill-rakers short, about 12 on lower limb of first 

 arch; lateral line complete, very sHghtly decurved; scales rather large, 

 striate, II or 12 in advance of dorsal, 9 to 11 between dorsal and adipose, 

 7 or 8 longitudinal rows between anterior rays of dorsal and lateral line; 

 dorsal fin inserted a Httle nearer tip of snout than base of caudal, the 

 anterior rays longest, reaching past tips of posterior rays; adipose fin 

 about one-third as far from base of upper caudal ray as from base of 

 last dorsal ray; caudal fin forked, the lobes of about equal length; anal 



