518 PROCEEDINGS OF THE ACADEMY OF [Oct., 



Eighteen young examples, of which one is figured, from tributaries 

 of the Madeira River near Porto Velho. January and February, 

 1913. In color they are pale uniform brownish, without spots or 

 other markings. The singular pectoral fin of these specimens first 

 attracted my attention, as it is composed of a rather long basal 

 fleshy lobe surrounded by the rays, which are given out from all 

 sides, except in front. That these specimens are identical with the 

 present species appears to me unquestionable. This is of importance 

 as two recently proposed genera are therefore very likel}^ parallel 

 cases. I refer to Archecheir Eigenmann and Dermatocheir Durbin. 

 Archeicheir is thus doubtless a synonym of the earlier (by page 

 priority) Poecilohrycon Eigenmann, and Dermatocheir is synonymous 

 with Hijphessobrycon Durbin. 



Curimatus tigris sp. nov. Fig. 2. 



Head 2|; depth 2f ; D. ii, 8; A. ii, 8; P. i, 10; V. i, 8; about 

 38 scales in median lateral series from shoulder to caudal base; 

 about 19 scales in transverse series between dorsal and ventral 

 origins; about 15 predorsal scales; head width 2 in its length, 

 measured from mandible tip; head depth at occiput If; first branched 

 dorsal ray 1^; first branched anal ray If; upper caudal lobe lyV; 

 least depth of caudal peduncle 2*; length of pectoral 2f ; ventral 

 2|; snout 3f in head, measured from upper jaw tip; eye 3|; mouth 

 width 3|; maxillary 4|; interorbital 3. 



Body elongately ovoid, well compressed, predorsal slightly con- 

 stricted, postdorsal with slight median groove, pre ventral rounded 

 convexly, and postventral constricted. Body deepest at dorsal 

 origin. Caudal peduncle well compressed, and measured from last 

 anal ray base, about long as deep. 



Head large, compressed, broader above, more or less flattened 

 sides constricted below, and profiles similar. Snout nearly straight 

 in profile, convex over surface, and length about f its width. Eye 

 large, rounded, high, placed near first f in head. Eyelid free, not 

 adipose-like. Pupil moderate. Mouth with short commissure, 

 broad, opens superiorly and broadly in front. Lips broad, rather 

 fleshy, smooth. Maxillary not very distinct, scarcely free, and 

 extends back to hind nostril. Each jaw with a row of small, flexible, 

 weak, conic teeth. Mandible with broad rami, slightly protrudes 

 beyond snout tip, elevated and swollen in mouth and fitting in 

 corresponding large cavities in upper jaw on each side posteriorly. 

 Tongue not evident. Nostrils together, anterior simple pore and 

 posterior in crescent, both faUing close to eye near last fourth in 



