EIGENMANN: TETRAGONOPTERID CHARACINS. 95 



Astyanax symmetricus, sp. no v. 



Allied to A. asymmetricus, A. anterior, and A. zonatus. Distinguished by the 

 absence of a humeral spot and the nearly symmetrical caudal spot. Most nearly 

 like A. zonatus^ from which it differs, among other things, by the striation of the 

 scales. 



Head 2.66 ; depth 2^\ ; D. 11 ; A.. 30; scales 8-48-6 ; eye 3 ; interorbital 2.66. 



Brassy ; a silvery lateral band ; no trace of a humeral spot ; middle caudal rays 

 dark, the chromatophores scattered over base of neighboring rays. 



One specimen, 74 mm. long. Tabatinga. 



Astyanax zonatus, sp. nov. 



Allied to anterior and asymmtericus ; distinguishable from other members of the 

 genus by a caudal " cross-bar." 



Head 3.8 ; depth 3 ; scales 8 or 9-42 to 47-5 or 6; D. 11; A. 27-30; eye 

 2.56 in head ; interorbital about equal to eye. 



A faint vertical humeral spot, a spur of it crossing the third scale of the lateral 

 line ; end of caudal peduncle vrhitish ; a broad, dark bar crossing base of caudal, 

 blackest in the centre, where it is continued to the end, or nearly to the end of the 

 middle rays. A narrow, silvery lateral baud. 



Alimentary canal not quite equal to the entire length. 



Six specimens, 34 (to base of caudal) to 59 mm. long. Tabatinga. 



Astyanax anterior, sp. nov. 



Allied to A. asymmetricus ; distinguishable from all other species of Astyanax by 

 the anterior position and sublinear character of its humeral spot. 



Head 3.5; depth 2.8; D. 11; A. 28-32; scales 9.5 or 10-52 or 53-56; eye 

 3 + ; interorbital 3. 



A silvery lateral band about three in the eye ; a horizontal black spot one-fourth 

 as wide as eye and rather longer than the eye, beginning on upper part of the 

 first scale of the lateral line and extending straight, pointed behind ; middle cau-. 

 dal rays black. Otlierwise plain. 



Two specimens, 70 to 91 mm. long. Tabatinga. 



Astyanax bourgeti, sp. nov.i 



A well-marked species, differing from all others of the genus in the black lower 

 fins. 



Head 3.33; depth 2.33; D. 11; A. 34; scales 12-53-9; eye a little less than 

 ^ length of head ; interorbital 2.47: 



1 In memory of Monsieur Bourget, who collected the species described as new in 

 this paper from Tabatinga. 



