526 PROCEEDINGS OF THE ACADEMY OF [July, 



Scales small and roughened on the entire exposed surface; 22 from 

 origin of dorsal to lateral line and 24 from lateral line to origin of anal. 



Dark above, lighter below, with a distinct silvery lateral band just 

 above the lateral line. At the base of the caudal a black spot. 



A second specimen (45) of a Characinus, No. 9.969. 22 mm., also 

 from Pasito, agrees with the species just described in those characters 

 in which squamosus differs from the other species of Characinus, having 

 A. 54, lat.l., about 106 ; the general shape and dentition just as described 

 for the type of squa?nosus. It differs, however, in the most striking 

 way in color. In addition to the caudal spot the tip of the lower jaw, 

 a spot in front of the dorsal, a very large band on the proximal | of the 

 first 9 dorsal rays just above the base, and a small spot each at the upper 

 and lower margins of the origin of the caudal are jet black ; a fainter 

 small black spot in front of the anal. 



Head 3f ; depth 31; D. 12; A. 54. 



The color markings are so well defined and intense that it is scarcely 

 conceivable that they should disappear entirely in the adult, and yet 

 the similarit}^ in other respects is so great that we hesitate to give it a 

 separate name. 



80. Roeboides prognathus (Bouleuger). 



Twelve specimens (45, 73, 147), Pasito Laguna. 



I). 10; A. 48-54; lat. 1., 75-84; depth 2|-3; head 3^-34. 



A dark spot in the largest specimens above the lateral line, just 

 behind the end of the occipital process. 



A median oval black spot on middle caudal rays and end of caudal 

 peduncle. A black vertical line bordering the caudal i^eduncle l.K^hind 

 and ending above and below in slight enlargements. 



81. Roeboides microlepis (Reinh.). Pirai. 



Four specimens (79,139), Rio Paraguay at Asuncion. These speci- 

 mens differ considerably from those hitherto figured and described. 



D. 10 or 11; A. 53-56; depth 2i-2|; head 3f-4; lat. 1., 97-100; eye 

 3-3f. 



82. Salminus brevidens (Cuvier). Dora dillo (golden). 



Hydrocyon hrevidens Cuv., Mem. Mus. ,V, 364, PI. 27, fig. 1. Valenciennes 



in d.Orb', Voy. Amer. Sud. Poiss., 10, PI. 9 fig .3. 

 Salminus brevidens Miiller and Troschel, Hora? Ichthyol., I, 16 ; Steindachner, 



Fisch-Fauna des Cauca und Flusse bei Guayaguil, 31, 1S80. (Parana.) 

 Salminus maxillosvs Cuv. and Val., XXII p. 62; Castelnau, Anim. Anier. 



Sud. Poiss., 61, PL 30, fig. 2; Giinther. Cat. Fish. Brit. ]\Ius., V .3.50, 1S64; 



Giinther, Ann. and Mag. Nat. Hist., 1880, 13 (La Plata); Boulenger, 



Trans. Zool. Soc. Lond., XIV, 37, 1896. (Paraguay.) 



Three specimens (37, 89, 262), Rio Paraguay at Asuncion. A. 26; 

 lat. 1., 92-100. 



