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MEMOIRS OF THE CARNEGIE MUSEUM 



base of the occipital process, which is narrow and reaches, or nearly reaches, the 

 plate in front of the dorsal; humeral process spine-like; roof of mouth without teeth; 

 head covered with thin skin. 



Distribution. — All rivers from Buenos Aires to Guiana and Venezuela and 

 to the base of the Andes (1,800 feet in places); west of the Andes from northern 

 Peru to the Chagres river in Panama. 



DiSTBIBUTION OF PiMELODELLA AND TyPHLOBAGRUS. 



The species of this well-marked genus differ from each other in the length 

 of the adipose fin, the length of the barbels, the length of the pectoral spine, the 



