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PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 95 
areas behind and a smaller pale area in front; a silvery or darkish wide 
lateral band not continuing on caudal fin or at most only faintly dis- 
cernible on midcaudal fin rays of young specimens; caudal spot absent, 
pectorals reaching to or a little past pelvic insertion; each side of pre- 
maxillary with 4 teeth in outer row and 5 teeth in inner row, the last 
outer tooth minute; maxillary with one tooth. 
Astyanax abramoides Higenmann 
2b. Scales fewer than 45 from head to midecaudal fin base. 
3a. 
3b. 
Middorsal line in front of dorsal fin “‘naked,”’ i. e., scale row along acute 
edge of predorsal midline lacking anteriorly, margins of normal-sized 
scales at sides not crossing midline but just in front of dorsal fin may 
occur a few scales on middorsal line; scales on midline of belly in front 
of pelvics normal; maxillary with none or (?) only one tooth on each 
side; dorsal origin equidistant between tip of snout and midcaudal fin 
base or a little closer to former; humeral spot black, oval shaped and 
sometimes with a vertically projecting streak of pigment below it, spot 
otherwise in a pale area extending nearly to midline of back; blackish 
lateral band forming an elongate triangular black caudal streak cone 
tinuing to end of midcaudal fin rays; dorsal fin equal to head length; 
anal rays about ili, 27 to iii, 32; scales about 7 to 9-36 to 42-7 to 9; 
Astyanax bimaculatus (Linnaeus) 
Middorsal line in front of dorsal fin with some scales along rounded or 
acute edge as large as those along its sides. 
4a. Proximal end of maxillary with 5 or 6 teeth; color pattern consisting 
of distinct wavy brown streaks parallel with scale rows; humeral 
black spot distinct; black lateral dark band intense posteriorly on 
caudal peduncle and continuing to end of midcaudal fin rays; dorsal 
fin longer than head and pectorals reaching past pelvic insertions; 
first rays of dorsal elongate on males; anal rays iii, 27 to ili, 29; scales 
40 to 42 from upper edge of gill opening to midcaudal fin base, 
usually 8 above and 6 below lateral line; gill rakers 9 or 10+12 to 14 
On) first sill Varch siamese Tah Anna Astyanax superbus Myers 
4b. Proximal end of maxillary with only one or two teeth. 
5a. Series of predorsal scales along middorsal line about half size of 
those at each side; midline of belly in front of pelvics with a row 
of minute or small scales, inner margins of adjoining row of normal- 
sized scales on each side with truncate margins that do not cross 
midline of belly; depth about 2 to 2.2 in standard length; 4 teeth 
in outer row and 5 in inner row on each side of premaxillary; dorsal 
fin much longer than head; humeral spot black surrounded by a 
pale area; black caudal spot oval but not continuing to end of 
midcaudal fin rays; anal rays iii, 29 to iii, 37, usually iii, 33 or lil, 34; 
scales 8-37 to 39-6 or 7. 
Astyanax magdalenae Higenmann and Henn 
5b. Series of scales along middorsal line in front of dorsal fin of same 
size or nearly so as those in adjoining rows; scales on belly in 
front of pelvics norma] in shape and in normal rows, not as in 5a; 
depth 2.5 to 3.1 in standard length. 
4 teeth in outer row and 5 in inner row on each side of Dre metary : 
greatest depth in large adults 2 to 2.6 and in young 2.9. 
6a. Black on middle caudal fin rays most intense on inner 4 rays of 
upper caudal fin lobe; practically no black pigment on inner 
ray of lower caudal lobe; a black band along base of anal con- 
tinuing posteriorly to form black caudal spot, thence on middle 
