1913.] NATURAL SCIENCES OF PHILADELPHIA. 529 



close behind dorsal base, first branched ray longest, extends 1| to 

 caudal base, and lower edge emarginate. Pectoral low, pointed, 

 upper rays longest, and fin extends about | to ventral. Ventral 

 inserted slightly behind dorsal origin, and extends to anal origin. 

 Vent formed at last fourth in space between ventral and anal origins. 



Color in alcohol pale brownish, paler or more whitish below. 

 Scales on back with their edges rather broadly dusted with dusky 

 dots. Also a patch of dusky dots above base of anal. Upper 

 surface of head with dusky dots, lower surface silvery or whitish. 

 Iris largely silvery, though pupil and broad vertical transverse bar 

 slaty to dusky. Concurrent with vertebral axis, a narrow, pale, 

 dusky line extends from behind shoulder, widens a little over anal, 

 then contracts and . ends medianly at caudal base. Latter with 

 large, black, rounded spot about size of eye. Fins otherwise all pale 

 or grayish. Peritoneum shows through walls of abdomen as whitish, 

 though posterior region showing cluster of dusky dots on costal 

 region posteriorly and belly anteriorly. 



Length 41 mm. 



Type, No. 39,193, A. N. S. P. Tributary of Rio Madeira near 

 Porto Velho, Brazil. January-February, 1913. Edgar A. Smith. 



Also Nos. 39,194 to 39,209, A. N. S. P., paratypes, same data. 

 Head 3| to 3f ; depth 2| to 3; D. in, 8, i or iii, 9, i; A. in, 21, i 

 to III, 23, i; scales 32 to 34 in 1. 1. to caudal base, and 2 or 3 more on 

 latter; 6 scales above 1. 1.; 4 or 5 scales below 1. 1.; 11 or 12 predorsal 

 scales; snout 3| to 4 in head; eye 2| to 3|; maxillary 3| to 4; inter- 

 orbital 2t to 3; length 33 to 43 mm. 



This species differs from Odontostilbe fugitiva Cope in its deeper 

 body and absence of the dark-edged silver lateral band. From the 

 other known species it differs in coloration and proportions. 



(Named for the Madeira River.) 

 Odontostilbe drepanon sp. nov. Fig. 7. 



Head 3i; depth 3|; D. ii, 8; A. in, 21, i; P. i, 11; V. i, 7; 

 scales 35 in 1. 1. to caudal base and 3 more on latter; 6 scales above 

 1. 1.; 5 scales below 1. 1. to ventral origin; 6 scales below 1. 1. to anal 

 origin; 9 predorsal scales to occipital process; head width 2| its 

 length; head depth at occiput U; snout 3|; eye 3^; maxillary 3^; 

 interorbital 2|; least depth of caudal peduncle 2f; third simple 

 anal ray 1|; pectoral 1|; ventral 1|. 



Body elongate, well compressed, contour elongately ellipsoid, 

 deepest at dorsal origin, lower profile anteriorly a little more convex 

 than upper, postventral slightly trenchant, and other edges convexly 



