244 
BULLETIN OF THE BUREAU OF FISHERIES 
Class PISCES 
Order HETEROGNATHI 
Family I. CHARACINlDi?: 
The Characins 
Body variously shaped, usually more or less compressed; upper jaw mesially 
formed by premaxillaries, laterally by maxillaries; teeth various; scales present, 
usually cycloid, wanting on head; dorsal fin small, without spines; adipose fin 
usually present. 
KEY TO GENERA 
a. Teeth in upper jaw in 2 series, none of them directed forward; anal fin of moderate length; 
usually composed of less than 30 rays Astyanax, p. 244. 
oo. Teeth in upper jaw more or less definitely in 3 series, the outer series composed of strong 
teeth situated on outer margin of jaw and directed forward; anal fin very long, usually 
composed of 45 or more rays Rwboides, p. 246. 
1. Genus ASTYANAX Baird and Girard 
Astyanai Bainl and Girard, Proc., Ac. Nat. Sei., Pliila., VII 1804 (Ib.W), 211 (type Aslyunai aryentutas Baird and Girard). 
Body more or less elongate, compressed, the depth usually more than 2 in length; 
second suborbital narrow, leaving a naked triangular area below suture between 
first and second suborbitals; premaxillaries with 2 series of teeth, the first with 
several teeth on each side, the second equal or graduated, usually 10, sometimes 8 
in nimaber; lower jaw with strong teeth anteriorly, usually abruptly smaller, conical 
ones on sides; maxillary with a few or no teeth; gill rakers setiform; lateral line 
complete; no predorsal spine; adipose fin present; anal fin of moderate length, 
usually of fewer than 30 rays; caudal fin naked. 
1. Astyanax fasciatus aeneus (Giinther) 
Plate ADA; Sardina 
Tetragonopterus serteus Giinther, Proc, Zool. Soc. London, 1860, 319 (Oxaca, Mexico). 
Astyanax fasciatus seneus Eigenmann, Memoir., Mus. Comp. Zool., XLIII, Part 3, 1921, 306. (A complete synonomy is given 
here by Eigenmann, to which the reader is referred for further references.) 
Head 3.5 to 5.13; depth 2.3 to 4.05; D. 11; A. 25 to 31; scales 33 to 38. 
Body compressed, variable in depth and thickness; profile almost straight over 
the head, convex from nape to dorsal; caudal peduncle strongly compressed, 
broadly rounded underneath, its depth 1.85 to 2.55 in head; head small; snout 
blunt, 3.25 to 4.1 in head; eye 2.75 to 4.3; interorbital 2.45 to 3.1 ; mouth moderate, 
terminal; maxillary reaching to or slightly past anterior margin of eye, 2.5 to 3 in 
head; teeth strong, mostly tri- to multicuspid, in 2 series on the premaxillaries, the 
outer series with 8, the inner with 10 teeth, 2 teeth on each maxillary, 8 or 9 large 
teeth anteriorly on the lower jaw and abruptly smaller ones laterally; gill rakers 
short, 11 to 14 on the lower limb of the first arch; lateral line complete, slightly 
decurved; scales rather large, 10 to 12 rows crossing the back in front of dorsal, 10 
