* . — and its Tributaries. 31 
-arated by a longitudinal sulcation ; nose obtuse, somewhat 
conical, projecting beyond the mouth ; nostrils large, on a line 
. With the eye. Eyes oblong-oval; iris silvery, and slightly 
gilt, on inner margin ; pupils black, operculum and preopercu- 
lum smooth, lustre bright silvery. Mouth diagonal, and when 
closed the lower lip is nearly concealed beneath the snout. 
Body elongated, slightly compressed laterally ; back rises 
. rapidly from the head to the dorsal fin, from thence to the tail 
it slopes more gradually and uniformly. Abdomen expands 
- beneath the pectoral fin and then continues of the same size to 
. the vent. It then rapidly diminishes to the tail. Lateral line 
straight, except that near its base it curves as ugh as the 
upper edge of the operculum. 
Dorsal fin elevated, trapezoidal ; caudal elongated, bilobed, 
with the tip of each lobe acute; anal jin falls short of the - 
* dorsal; ventral horizontal, and reaches to the vent; pectoral 
: we nearly horizontal, does not attain to the ventral by 
| an inch. 
_ Length 8 inches. Head 12inch. Tail 15. zt of the 
ý body at the commencement of the dorsal fin ik 
_ Color. Back and upper surface of the body id head oli- 
' *vaceous, sides silvery, and of a brilliant metallic lustre, with a 
nt. Three or four exterior rays of each lobe of the caudal 
» Sometimes milky and opaque, and the intervening — ! 
B5; 0.99: ADs: V9; B. T 
^. I formerly considered it a variety of the R. plugiv 
f. but farther observation has satisfied me that it is a 
4 bowel band extending the whole length of the lateral line. 
Pectoral and ventral fins yellowish, anal white and trans- 
