6S S(/?ioj)sis of the Fresh Water Fishes, 



rays are more than tliree quarters of the length of the dorsal's ; 

 the subsequent rajs gradually decrease in length towards the 

 posterior portion of the fin, but the last three or four rays are 

 produced beyond the others as in the C. Biisei. 



D. 9. A. 31. P. 10. V. 6. 



The color is, as in the preceding species, silvery green above, 

 and white beneath, with a black line posteriorly on the sides 

 and caudal peduncle ; there is also a rose-colored band, in the 

 living animal, on each side. 



Genus. 

 Kematopoma,* Gill. 



Body subfusiform, compressed, covered by moderate scales ; 

 abdomen convex and rounded. 



Head compressed, with the profile sub-conical. 



Mouth opening obliquely upwards, moderate, with the gape 

 elongated elliptical. Lower jaw advanced beyond the upper, 

 but with its single row of teeth received in the space between 

 the outer and inner rows of the latter. 



Teeth in two rows on the intermaxillaries, and in a single 

 one on the dentaries; they are broad, compressed, wdth the 

 crowns multicuspid, and with the middle cusp longest. 



Nasal apertures near the antero-superior border of the eyes ; 

 the posterior one is much larger. 



Operculum with a triangular spiniform dilatation, which is 

 continued from the apex into a very long slender setaceous 

 filament, w^hich has a compressed dilatation at the extremity. 

 Cheeks entirely covered by the large third suborbital. 



Lateral line deflected for a short distance from the mastoids, 

 and thence running in a nearly straight course to the caudal. 



Dorsal posterior, above the middle of the anal, with the base 

 short, and with the height very great. 



* Formed from N^/za, a thread or filament, and Hco/za, operculum, in reference 

 to the slender filament of the operculum. 



