NATURAL SCIENCES OF PHILADELPHIA. 261 



TETRAGONOPTERUS PH(ENICOPTERUS, Cope. 



D. 10 ; A. 26-T ; ventrals originating iu front of dorsal, not 

 reaching anal ; pectoral reaching ventral. Scales 5|— 35-4. Depth 

 of body 3.3 times in length without caudal ; length of head 4.2 

 times. Orbit 2.5 times in head, equal the plane interorbital space. 



Silvery, with lateral silver band and indistinct scapular and 

 basal caudal blackish spots. Anal and dorsal fins vermilion ; 

 caudal with a triangular vermilion spot which surrounds the 

 basal black spot, and whose apex reaches the caudal emargiua- 

 tiou. 



Length .053 m.; to dorsal .021; to anal .0245. 



Apparently very abundant. It is allied to the T. cm^olinee of 

 Dr. Gill (Proc. Ac. Nat. Sci., Phila.), 1870, p. 92, but is a more 

 slender fish with smaller head. 



STETHAPRION CHRYSEUM, Cope, sp. nov. 



Form elevated, disciform ; scales small, 19-67-16. Radii D. 

 12 ; A. 37 ; Y. 8, very small, not reaching anal, and comraencino- 

 below dorsal. Pectoral falcate reaching nearly to line of end of 

 ventrals. Base of anal fin covered with scales, especially ante- 

 riorly ; dorsal with a long decurved spine in front of it. Caudal 

 peduncle contracted. Depth into length less caudal fin, 1.66 

 times, length of head 3.4 times. Orbit 2.4 times in head, much 

 larger than muzzle's length, 1.1 times in interorbital width. Pro- 

 file of head very concave. Dorsal fin elevated, caudal deeply bi- 

 furcate. Lateral line a little decurved medially. 



Color silvery, a leaden shade from postscapular region to caudal 

 fin, darkest in front at a postscapular spot. Below this band, 

 yellow. Fins unspotted. Total length .071 m. ; to dorsal fin (ob- 

 lique) .03 ; to caudal (straight) .053 ; to ventrals (oblique) .032 m. 



This species is near the type S. erythrops, Cope (Proc. Am. 

 Phil. Soc, 1870, p. 562, fig. 5), but has larger scales and a different 

 coloration. The genus Slethaprion has the physiognomy of My- 

 leles, but is essentially near to Tetragonopterus. It differs from 

 the latter chiefly in the decurved spine in front of the dorsal fin, 

 a character it shares with Herrasahno. 



BRYCON CAPITO, Cope, sp. nov. 



Scales small, L. 1. 56, 1. tr. 25. Depth of body one-fourth, 

 length of head one-third of total without caudal. Radii D. 10 ; 

 1872.] PART III.— 18 



