524 PROCEEDINGS OF THE ACADEMY OF [Oct., 



broadly convex. Cheek without distinct suborbitals. Preopercle 

 edge nearly vertical. Opercle rather large, smooth. Slight fontanel 

 at anterior junctions of parietals with frontals medianly. 



Gill-opening extends forward about opposite preopercle edge. 

 Rakers moderate in number, lanceolate, on both branches of gill- 

 arch, and a little shorter than filaments. Gill-filaments about | of 

 eye. Gill-membranes united, form free fold across isthmus, which 

 convex and constricted. 



Scales large, cj^cloid, broadly exposed in nearly even longitudinal 

 series apparently' without striae, and of nearly uniform size. No 

 scales on fins, no 1. 1., and no axillary scaly flaps. 



Dorsal inserted posteriorly, its origin a little nearer caudal base 

 than hind edge of eye, first branched ray longest, and depressed fin 

 extends If to caudal base. No adipose fin. Caudal forked, lobes 

 pointed, free and equal. Anal inserted below last branched dorsal 

 rays basally, first branched ray longest, and depressed fin extends 

 1^ to caudal base. Pectoral low, rounded, moderate, and reaches 

 14 to ventral. Ventral inserted well before dorsal, or nearly midway 

 between pectoral and anal origins, fin extends 1| to anal. Vent 

 close before anal. 



Color in alcohol pale straw-brown, back slightly dusted with 

 minute dark dots, mostly formed closer along edges of scales above. 

 Lower surface of body immaculate. Including mandible tip, then 

 over preorbital across iris, preopercle and lower side medianly to 

 bases of median inferior caudal rays, a blackish band made up of 

 close-set dusky dots. This band narrow on head, though widens 

 over costal region to contract slightly along caudal peduncle laterally. 

 On caudal base dark lateral band reflected out on some of rays. 

 Iris slaty and orbital boundaries well defined on lower surface of 

 head, where their dark color strongly contrasts with white of mandi- 

 ble. Dorsal with large conspicuous black blotch, extends vertically 

 over fin from upper front edge to near bases of last branched rays. 

 Except for markings noted above, fins otherwise pale or whitish. 



Length 15 mm. 



Type, No. 39,188, A. N. S. P. Tributary of the Madeira River 

 near Porto Velho, Brazil. January or February, 1913. Edgar A, 

 Smith. 



This species differs from all of the others in the genus in the black 

 dorsal, blotch. Only the type known. 



{IriyiJ.a^ spot; Trjiitwv^ banner; with reference to the dark blotch 

 on the dorsal fin.) 



