362 MEMOIRS OF THE CARNEGIE MUSEUM 



Elongate, subrhomboidal, profile rising rapidly in front, then curved more 

 gently to the dorsal; ventral profile regularly rounded. Preventral area convex, 

 without a distinct median series of scales; postcentral area narrowly rounded; 

 predorsal area narrowly rounded, two scales in front of the dorsal, the median line 

 otherwise naked to the occipital process. 



Occipital process very narrow, its width not quite half its length, which is 

 about one-fifth as long as the distance from its base to the dorsal, bordered by three 

 scales on the sides. Interorbital smooth and convex; frontal fontanel a little 

 narrower and a little shorter than the parietal; second suborbital leaving a con- 

 siderable naked area, which is widest below; mouth large, maxillary a little longer 

 than the eye; normally four teeth in the outer series of the premaxillary, of which 

 the third is withdrawn from the line of the rest; five teeth in the second series; maxil- 

 lary with three small teeth; mandible with four large teeth in the dentary and 

 abruptly minute ones on the side. 



Gill-rakers 6 + 14, those of the upper arch excessivel^v minute, those of the 

 lower arch about one-third the length of the eye. 



Scales of the sides regularly imbricate, no interpolated scales over the anal; 

 scales of the ventral surface less regularly imbricate; lateral line but little decurved; 

 anal sheath composed of a single series of scales along the base of the anterior rays. 



Ventrals but little nearer the snout than to the dorsal, which is a little nearer 

 to the snout than to the caudal; highest dorsal ray about 4 in the length. Anal 

 emarginate, the second and fourteenth rays reaching the base of the twentieth ray. 

 Ventrals not reaching anal, pectorals just to ventrals. 



Coloration much as in abramoides. A dark bar crossing opercle, a second bar 

 some distance behind this in a light area, the second bar widest above the lateral 

 line, where it forms an indistinct humeral spot; a third bar shading into the thickly 

 dotted sides; cheeks thickly punctate; a dark dorsal streak. A black band crossing 

 the base of the caudal and sometimes extending out along the outer rays. No 

 dark line along the sides in formalin specimens, but sometimes dark streaks up and 

 down from the median line between the muscle segments. 



Ctenobrycon Eigenmann. 



Ctenobrycon Eigenmann, Bull. Mus. Comp. Zool., XLI, 1908, 94. 



Type, Tetragonopterus hauxwellianus Cope. 



Distinguished from all other Tetragonopterids by its ctenoid scales. 



Anal long, its margin nearly straight, its origin behind or below the origin of 

 the dorsal; mouth very small, the maxillary not reaching the eye; scales of the 



