1911.] NATURAL SCIENCES OF PHILADELPHIA. 505 



(damaged) well forked, lobes apparently pointed and slender, also 

 likely equal ?, and fin about equal to head in length ?. Anal origin 

 about opposite last dorsal ray base, first branched ray longest, 

 though second and third branched and fourth simple subequal, with 

 anterior rays of fins thus much longer than others, and last fin ray 

 about half way to caudal base. Pectoral long, rather slender, upper 

 rays longest, and fin extends a little beyond ventral origin. Latter 

 inserted before dorsal, though nearer anal origin than pectoral, and 

 depressed fin reaching anal origin. Vent close before anal. 



Color in alcohol largely brownish or dull olivaceous, with lilac 

 tinge on back, sides and lower surface brilliant silvery- white. In 

 some lights body more or less reflected greenish or lilac. Head 

 above olivaceous-brown, color including upper lip and upper portion 

 of maxillary, sides and lower surface, silvery-white, mandible pale. 

 Iris silver-gray, varied, with narrow golden circle around pupil. 

 Inside gill-openings pale. A short, narrow and rather dull vertical 

 leaden streak opposite eye after and superior to third scale in 1. 1. 

 Caudal peduncle, at caudal base, with a large dusky blotch, equal 

 to the eye in extent, extending out on caudal base, and reflected 

 back to include median caudal rays as a dusky streak, though latter 

 a little paler than blotch. Dorsal grayish, membranes medianly 

 tinged with dusky. Caudal grayish, edges of fin all slightly dusky. 

 Other fins pale or whitish, membranes of anal grayish distally. 

 Peritoneum rather dusky. 



Length 3f 5 6 inches (caudal tips damaged). 



Type, No. 7. Collection of S. N. Rhoads. Affluent of the Chimbo 

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



In the accompanying figure I have restored the caudal fin ends. 



This species differs from Brycon atrocaudatus (Kner) 2 in the dark 

 humeral blotch. If, as Boulenger suggests, 3 B. moorei Steindach- 

 ner 4 is identical with B. atrocaudatus (Kner), B. scapularis further 

 differs in the absence of an inner lateral mandibular series of simple 

 or conic teeth. Steindachner says of B. moorei that the dark 



2 Chalceus atrocaudatus Kner, Sitz. Ak. Munch., II, 1863, p. 227. Western 

 Andes of Ecuador. 



Kner and Steindachner, Abh. Kon. Bayer. Ak. Wiss., X, 1S70, p. 44, 



PI. 4, fig. 3 (type). 



3 Brycon alricaudatus Boulenger, Boll. Mus. Z. Anat. Torino, XIII, No. 329, 

 1898, p. 3. Paramba, in Rio Mira. 



4 Denks. Ak. Wiss. Wien, XXXIX, 1879, p. 58, PI. 5, figs. 2, 2a, 26. Magdalena 

 River. 



