ElGENMANN : COLLECTIONS OF FlSHES FROM PARAGUAY. 127 



a depth equal to half the length. It is more than probable that the 

 Astya?iax multiradiatus of Eigenmann and Kennedy is a species dis- 

 tinct from Steindachner's. 



Head 4 ; depth 2 ; D. 1 1 ; A. 40-41 ; scales 1 1-50-8. 



Compressed, more elongate than in argenteus ; anterior profile con- 

 cave: Snout blunt, interorbital convex. Eye 2^ in head, not equal 

 to the interorbital, j£ longer than snout. Maxillary small, not reach- 

 ing to below eye ; no teeth on maxillary. 



Origin of dorsal equidistant from tip of snout and base of middle 

 caudal rays or nearer the former, inserted distinctly behind the ven- 

 trals, not falcate, the longest ray not nearly reaching adipose ; anal 

 not falcate, the rays of nearly the same height its entire length ; 

 ventrals about reaching anal ; pectoral a little beyond origin of 

 ventrals. 



A faint humeral and caudal spot, an indistinct silvery lateral band, 

 fins gray, outer pectoral ray dark. 



Astyanax Baird and Girard. 



Astyanax Baird and Girard, Proc. Acad. Nat. Sci., Phila., Vol. 

 VII., p. 27, 1854 ( K argentatus~) . 



Pcecilurichthys Gill, Ann. N. Y. Lye. Nat. Hist., 1858, p. 54, 

 {brevoortii = bimaculatus") . 



The genus Astyanax is one of the oldest and most widely distributed 

 genera of South American Characins. It is now one of the dominant 

 South American genera, being found from the Rio Negro on the bord- 

 ers of Patagonia to the United States, and on both slopes from Peru 

 north to Mexico. Its counterpart is found in Africa as Petersius. 

 It has hitherto been associated with a number of other genera under the 

 name Tetragonopterns with the following characters : 



Premaxillaries with two series of multicuspid teeth, none of them 

 enlarged ; maxillary with or without teeth ; mandible with a single 

 series, those in front very strong, graduated and multicuspid, those 

 of the side abruptly minute and usually conical ; gill-rakers setiform ; 

 no predorsal spine ; maxillary short ; the snout and maxillary together 

 less than half the length of the head. 



The species with the characters just noted represent several genera 

 which may be divided as follows : 



a. Caudal and anal both naked. 

 b. Lateral line interrupted. 



