62 Annals of the Carnegie Museum. 



fourths of the greatest depth. Preventral region rounded, without 

 complete series of median scales. Postventral region narrow. Pre- 

 dorsal region rounded, probably with a complete series of nine median 

 scales. 



Occipital process about one-sixth of the distance from its base to the 

 dorsal, bordered by two or three scales on the sides. Interorbitals 

 slightly convex. Frontal fontanel triangular, narrower than the parie- 

 tals and not quite equal to the parietal without the occipital groove. 

 Second suborbital leaving narrow naked margins behind and below. 

 Snout a little more than one-half the length of the eye. Mouth large. 

 Maxillary equal to the eye, narrow, slightly curved backwards, the 

 two sides parallel to each other. Mandible equal to the maxillary. 

 Premaxillary with three tricuspid or conical teeth in the outer row and 

 five three- to five- or rarely seven-pointed teeth in the inner row. 

 Maxillary with one to five tricuspid or conical teeth. Dentary with a 

 graduated series of four or five large three- to five-pointed teeth. 



Gillrakers 7 + 14. 



Scales cycloid, regularly imbricate, no interpolated scales or rows 

 of scales. Striae few, variable in number. Caudal with three to five 

 scales on the base of each lobe. Anal sheath short, of three scales 

 covering the base of the first six anal rays. Lateral line with pores 

 developed on about seven scales. Only slightly decurved. 



Origin of the dorsal equidistant from the snout and caudal, penulti- 

 mate ray one-third of the longest, which is 3.5 in the length. Origin 

 of the anal on the vertical from last dorsal ray. Anal deeply emargi- 

 nate ; the longest ray about 0.8 of the base. Base of ventrals on the 

 vertical from the second scale in front of the dorsal. Ventrals just 

 reaching anal. Pectorals just reaching ventrals. 



A diffuse round, or somewhat vertically elongate, humeral spot. A 

 dark lateral stripe heaviest behind the origin of the anal, but not reach- 

 ing the base of the caudal. No caudal spot. A black line at the base 

 of the first anal rays not continuous with that at the base of the first 

 seven. Dorsal, caudal, first seven rays of the anal, and first two or 

 three rays of ventrals, dusky. Scales of the back dusky, each often 

 bearing a single black spot. 



Hemigrammus cylindricus sp. nov. 



Type, 57 mm. (No. 1461 Carnegie Museum Catalog of Fishes.) 

 Tumatumari. 



