312 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 92 
gill membranes mostly free from isthmus, joined far forward; scales 
ciliated, 32 to 36, 10 in a transverse series to pelvic base; 13 or 14 
scales before dorsal fin; dorsal rays iii, 7 or 8; anal iii, 6 or 7; gill 
rakers about 10 on lower part of first arch; a black lateral band from 
snout to tips of caudal fin rays____-_ Neolebias unifasciatus Steindachner 
1b. Teeth in outer row caninelike or short and bluntly conical; upper jaw not 
movable; lateral line complete; gill membranes free from isthmus. 
38a. Scale rows more numerous than 40, crossing sides of body; outer row 
of teeth strong canines. 
4a. Scales about 47, 744 above lateral line and 2% below it to pelvic fin 
base; 18 scales before dorsal; dorsal rays ii, 8; anal iii, 14; gill 
rakerg 7 or 8 + 10. Color.—Lengthwise brown streaks along each 
row of scales on sides of body; adipose fin black. 
Hydrocyon forskali Cuvier 
4b. Seales about 61, 91% above and 4% below lateral line; about 42 scales 
in front of dorsal fin; dorsal rays ii, 7; anal iii, 9; gill rakers 541+ 
10; adipose fin blackish; 3 black streaks and 2 white ones between 
them radiate backward from eye, another white streak below eye. 
Hepsetus odo (Bloch) 
3b. Scale rows crossing sides 20 to 33; outer row of teeth short, bluntly 
conical; dorsal rays ii or iii, 8. 
5a. At tip of lower jaw occurs a pair of short conical caninelike teeth in- 
side the outer row of multifid teeth. 
6a. Anal rays iii, 18 to 20; scales 29 or 30, 51% above and 21%4 below 
lateral line; about 18 scales in front of dorsal fin; gill rakers 9 or 
10 + 12 to 15; a large, oblong black blotch on caudal peduncle 
extending to tips of mid-rays of caudal fin. Depth 2% (males) to 
3% in Standard length; origin of dorsal from midway (seldom) 
to a little closer to tip of snout than base of caudal fin; least 
depth of caudal fin 2% to 21% in head. 
Alestes longipinnis (Giinther) 
6b. Anal rays 11 to 15; gill rakers 12 to 14 + 16 to 19. 
Ta. Anal rays iii, 14; scales 25 to 27; 51% above and 1% below the 
lateral line to base of pelvic fin; 9 scales before dorsal; a black 
blotch on caudal peduncle, not extending on caudal fin rays; a 
faint blotch behind head near midaxis; posterior margin of anal 
fin blackish; depth about 2%4 to 3 in standard length; origin of 
dorsal a trifle closer to tip of snout than of caudal fin; least 
depth of caudal peduncle 24% in head__-_- Alestes nurse (Riippell) 
7b. Anal rays iii, 12 or 18; scales 23 to 26, 4144 above and 1144 below 
lateral line; 9 or 10 scales before dorsal fin; a black oblong 
blotch on caudal peduncle that extends to tips of midcaudal fin 
rays; a black blotch behind head; depth 3%4 in standard length; 
origin of dorsal fin nearly an eye diameter closer to base of 
caudal fin rays than tip of snout; least depth of caudal peduncle 
2G in Nea Ses kee es 2 ee Alestes rutilus Boulenger 
56. At tip of lower jaw, no pair of conical teeth within the outer row of 
teeth; anal rays iii, 15 or 16; scales 24 to 26, 41% above and 1% be- 
low the lateral line; gill rakers about 6 + 13; a blackish lateral band 
narrow and obscure anteriorly but distinct and wider posteriorly, not 
extending on head nor on caudal fin; tip of dorsal black. 
Petersius occidentalis (Giinther) 
