102 FISHES OF WESTERN SOUTH AMERICA 
ing, done in the interest of safety. Specimens in the markets are invariably marred 
in this respect, although perfect otherwise. 
42. PIMELODELLA GRACILIS (Cuvier and Valenciennes) 
Pimelodus gracilis Cuvier and Valenciennes, 1840, Hist. Nat. Poiss., XV, 181; 
Valenciennes, 1847, Voy. d’Orbigny, atlas IT, pl. 1, fig. 5; 
Giinther, 1864, Cat. Fish. Brit. Mus., V, 121. 
Pimelodella gracilis Eigenmann and Eigenmann, 1888, Proc. Cal. Acad. Sci., (2), I, 132; 
Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 153; 
EHigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 389; 
Eigenmann, 1917, Mem. Carnegie Mus., VII, 238; 
Pearson, 1937a, Proc. Cal. Acad. Sci., (4), XXIII, 92, Tingo de Pauca and Pusoc, upper 
Maranon. 
La Plata to the Orinoco 
Genus 15: PIMELODUS Lacépéde 
Pimelodus Lacépéde, 1803, Hist. Nat. Poiss. V, polygeneric sp.; 
Cuvier, 1817, Régne Anim., II, 203 (restricted to species having only a single band of teeth 
in the upper jaw); 
Swainson, 1837, Fish. Amph. Rept., II, 305, quadrimaculatus; 
Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sei, I, 162; 
Higenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 388; 
Eigenmann, 1912, Mem. Carnegie Mus., V, 171. 
Type: Pimelodus maculatus Lacépéde (Silurus quadrimaculatus Bloch) 
All South America southward to La Plata and westward to the Andes 
Edentulous palate (teeth on pterygoid in one species); vomerine teeth in small 
patches or wanting; fontanel not extending past the eyes; humeral process broad 
and not spine-like; crown of the head granulose; dorsal I, 6; dorsal and pectoral 
spines stout; eye with free orbital margin; barbels terete. 
43. PimeLopus pictus Steindachner 
Pimelodus pictus Steindachner, 1876, Sitzb. Kix. Akad. Wiss. Wien, LX XIV, 96, Peruvian Amazon; 
Eigenmann and Eigenmann, 1888, Proc. Cal. Acad. Sci., (2), I, 184, Hyavary; 
Eigenmann and Eigenmann, 1890, Oce. Papers Cal. Acad. Sei., I, 170; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 388. 
Peruvian tributaries of Amazon to Hyavary 
15754, 9, 97-105 mm., Rio Huallaga, Yurimaguas, Allen, November, 1920. 
15755, 1, 105 mm., Rio Paranapura, Yurimaguas, Allen, November, 1920. 
15756, 1, 92 mm., mouth Rio Pacaya, Allen, August, 1920. 
15757, 3, 94-104 mm., Rio Morona, Allen, August, 1920. 
Steep profile flattened on interorbital region; postorbital region much rounded 
transversely; occipital process keeled; head bones granular; premaxillary band of 
teeth projecting; vomerine teeth in small patches; eye 3.5 in head, 1.33 in the snout, 
1.2 in the interorbital; maxillary barbels extending slightly beyond base of adipose 
or to the caudal; mental barbels to the base of the pectoral; postmental to the tip 
