508 PROCEEDINGS OF THE ACADEMY OF [Sept., 



A narrow area of small scales all along anal base, though best devel- 

 oped anteriorly. In other respects all fins, together with head, 

 naked. Squamation passing completely over all edges of body. 

 No axillary pectoral scaly flap, though that of ventral pointed, 

 narrow, free and about 2f in fin. L. 1. complete, moderately decurved 

 till a little below median axis of body and then continued up a little 

 low along sides of caudal peduncle to median caudal base. Tubes 

 simple, at first little exposed and at most not extending more than 

 half-way in exposures of scales. 



Dorsal origin about midway between snout tip and caudal base, 

 first branched ray longest, second branched and third simple rays 

 subequal, and depressed fin a trifle over half way to caudal base. 

 Adipose dorsal origin a trifle behind last third in space between 

 dorsal origin and caudal base, fin nearly half way to latter. Anal 

 base long, straight, origin about opposite seventh dorsal ray base, 

 first branched ray longest with fourth simple and second branched 

 rays subequal, so that slight elevated lobe forms anteriorly. Caudal 

 well forked, lobes slender, pointed, and lower much longer (upper 

 a little damaged) or about equals head length with f of eye-diameter. 

 Pectoral long, upper rays longest, fin reaches trifle beyond ventral 

 origin. Latter inserted a little before dorsal origin, though a little 

 nearer anal origin than that of pectoral, and depressed fin reaching 

 anal origin. Vent about last fifth in space between ventral and 

 anal origins. 



Color when fresh in alcohol largely pale olivaceous-brown on back, 

 with sides becoming pale or whitish, also below, and whole overshot 

 with bright silvery- white. A broad silvery-white band extends 

 from eye to caudal base, width about equal to eye-diameter, this 

 conspicuously contrasting coloration of back with that of lower 

 regions. No dark humeral blotch. At base of caudal and on 

 contiguous region of caudal peduncle dusky blotch, this extending 

 out on median caudal rays to edge of fin, though area on latter paler 

 and variegated with deeper marblings. Head brownish-olive above, 

 color including all of upper lip, also lower lip. Head sides and below, 

 also iris, bright silver-white. Dorsal grayish basally, becoming pale 

 olivaceous distally. Anal similar, only largely tinged with pale 

 dusky on outer portions. Caudal grayish basally, edges of fin 

 slightly deeper. Pectoral and ventral pale grayish, distally slightly 

 deeper in color. Peritoneum dusky to blackish. 



Length 3| inches. 



Type, No. 8. Collection of S. N. Rhoads. Affluent of the Chimbo 

 River, near Bucay, Province of Guayas, Ecuador. July, 1911. 



