232 MEMOIRS OF THE CARNEGIE MUSEUM 



on the posterior face of the pectoral in specimens 83 mm. long, about 20-30 

 much more feeble ones in large specimens, the more distal thorns sometimes 

 with a broad base and a long free outer edge; maxillary barbels reaching origin, 



or beyond tip of adipose 2. cristata (Miiller & Troschel). 



dd. Caudal lobes subequal, always longer than the head; 18-29 thorns on the posterior 

 face of the pectoral spine; maxillary barbels reaching tip of adipose or beyond 

 tips of middle caudal rays; adipose fin 2.33 in the length; pectoral spine about 

 equal to the dorsal spine, sometimes shorter; dorsal spine 1-1.25 in the head. 



3. steindachneri Eigenmann. 



ddd. Upper caudal lobe normally greatly prolonged, but subequal in the young, not 



much narrower than the lower lobe; maxillary barbel always extending at 



least beyond base of anal; lateral band, if present, broad; pectoral spine a little 



longer or a httle shorter than the dorsal spine with a variable number of strong 



teeth on over half its posterior margin 4. gracilis (Cuvier & Valenciennes). 



dddd. Upper caudal lobe not produced; maxillary barbels reaching to tip of ventrals 

 or to middle of anal; about 11 teeth on the pectoral spine; adipose fin 2.75-3.25 



in the length 5. avanhandavce Eigenmann. 



ddddd. Upper caudal lobe not greatly produced; maxillary barbel reaching beyond tip of 

 ventrals; numerous minute teeth on the pectoral spine; lateral band ill-defined. 



6. roccm Eigenmann. 



dddddd. Upper caudal lobe not prolonged beyond the lower; maxillary barbels reaching 



origin of ventrals; pectoral spine smooth in front, with about nine thorns on 



the inner margin, the largest a little more than half the greatest width of the 



spine. No lateral band 7. puruensis Fowler. 



ccc. Pectoral spine smooth or but shghtly roughened behind; upper caudal lobe prolonged; 

 maxillary barbels reaching anal; lateral band narrow, well defined; dorsal spine equals 



pectoral spine 8. buckleyi (Boulenger). 



66. Adipose fin 3 or more than 3 in the length. (See also number 3). 

 e. Dorsal spine not produced into a filament. 



/. Pectoral spine with thorns along all but the very tip of the posterior margin; inter- 

 orbital three-fourths as wide as eye. 



g. Maxillary barbel extending to the origin of the adipose fin, nearly to tip of ventral ; 

 pectoral spine equals length of head; eye 4 in the head, interorbital 5. 



9. peclinifera Eigenmann & Eigenmann. 



gg. Maxillary barbel e.xtending beyond base of anal; pectoral spine much shorter 



than head; eye 3.33 in the head, interorbital 5.5; inner pectoral thorns large; 



a narrow dark band 10. hasemani Eigenmann. 



ggg. Maxillary barbel extending to end of the adipose; pectoral spine minutely serrate 



within and without 11. cyanostigma Cope. 



//. Pectoral spine with IS or fewer teeth, except in the very old. 



h. Eye large, 2.5 in the head; interorbital much smaller than the eye, 5.5 in the 

 head; lower caudal lobe much the longer; pectoral spine but little shorter than 

 the head; maxillary barbel reaching origin or end of base of anal. 



12. megalops Eigenmann. 

 hh. Eye smaller, more than 3 in the head. 



i. D. 1.7; pectoral spine reaching ventrals, which reach to the anal. 



13. brasiliensis Steindachner. 



