262 PROCEEDINGS OP THE ACADEMY OF 







A. 25 ; V. T (8?). Dorsal originating a little behind line of ven- 

 tral, pectoral reaching ventral. Orbit 2.66 times in head, equal 

 interorbital -width. Middle series of premaxillary teeth continued 

 outwards as far as the exterior. Posterior pair of mandibular 

 teeth very small. Color leaden, head silvery, a scapular and 

 large basal caudal black spot. 



Total length .06 m., to dorsal fin .0275, to anal .034. 



CHALCETJS MACROLEPIDOTTJS, Cuvier. 

 Cuv. Val. xxii. 240. Gunther, Cat. B. M. v. 333. 

 Two teeth only in posterior mandibular series. 



CHALCETJS EEYTHETJETJS, Cope. 

 Pletliodectes erythrurus, Cope, Proc. Am. Phil. Soc, 1870, p. 563, fig. 6. 



This species belongs to Chalceus, but differs from the type in 

 having scales of equal size. Gunther says of this genus in his 

 analytical key, " anal fin more or less elongate," as distinguished 

 from " anal short" of Piahucina^ yet C. maci^olepiclotus has as 

 many anal radii as P. erythrino'ides. Creagrutiis, with a fin of 

 about the same length, is placed in the " elongate" anal division. 



MEGALOBRYCON MELANOPTERTJM, Cope, sp. nov. 



Rather stout; dorsal outline arched. Length of head three and 

 three-fifths times in total lacking caudal fin, depth three times in 

 same. Orbit large, equal muzzle, 3.5 times in head. Radii D. 11 ; 

 A. 25; Y. 8, commencing opposite the third or fourth dorsal ray. 

 Pectoral just reaching ventral. Scales 1.1. 67, exposed surface 

 striate. Interorbital width 1.6 times diameter of orbit, gently 

 convex, less than postorbital length of head. Premaxillary teeth 

 in three series, the outer small, not in contact, equal to the maxil- 

 laries, and simple or with a minute cusp on each side; ten in 

 number on each bone. The posterior series is uninterrupted from 

 side to side, iucludiug six teeth on each side ; the median row 

 forms an open ^, the angles forwards. Caudal fin deeply forked. 



Total length seven inches, = m. .176; length to dorsal fin .071 m. 

 (straight) ; to anal .10 m. Color silvery, with a black band which 

 commences between the ventral fins, on each side of the base of 

 the anal, across the caudal peduncle, and along the middle of the 

 upper lobe of the caudal fin to its end; anal black at base, other 



[January 16, 



