SOUTH AMERICAN NEMATOGNATHI. 131 



Eye nearly median, slightly nearer tip of snout than 

 to edge of opercle, 5J-8 in head, 2-3| in snout, 1J-2J 

 in interorbital. 



Maxillary barbels extending past middle of adipose fin 

 in the young, scarcely to end of dorsal in adult; post- 

 mentals little beyond base of pectorals. 



Jaws subequal, the upper sometimes a little longer; 

 width of intermaxillary band of 

 teeth 2f-3 'in head, the band 

 rather deep, its depth 4-4 J in its 

 width; mandibulary band very 

 deep in front, tapering to a fine 

 point. Lips conspicuously papillose. 



Distance of dorsal spine from snout 2J in the length; 

 the length of the spine 2-2-J- in the head, the base of the 

 fin much longer than the highest ray. Distance of adi- 

 pose fin from the dorsal J-J the dorsal's base. Adipose 

 fin 3-3 J in the length. 



Caudal deeply forked, the lower lobe broader, 1J in 

 head. Tip of anal ray scarcely reaching the vertical 

 from the end of the adipose fin. Ventrals 1-f 2-J- in 

 head. 



Pectoral spine stout, recurved teeth on its anterior 

 margin, strongest near the tip of the spine, 2J-2f in 

 head. 



Color uniform brown. 



Head 3J-3|; depth 4J-6J; depth of caudal peduncle 

 9-10i; D. I, 7-8; A. 11-12. 

 91, Rhamdia hilarii. 



Pimelodus hilarii Cuvier & Valenciennes, xv, 180, 1840 (Kio San 



Francisco; Montevideo); Giinther, Cat. Fish. Brit. Mus. v, 



132, 1864 (copied). 

 Rhamdia hilarii Liitken, Dan. Selsk. Skr. 175, with figure, 1875, 



(Rio das Velhas); Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. 



i, 126, 1888 (Bon Jardin). 

 Habitat: Kio San Francisco and its tributaries; Porto Alegre south 



to Rio Plata. 



