76 CALIFORNIA ACADEMY OF SCIENCES. 



Oaleichthys elatturus Jordan, Proc. U. S. Nat. Mus. 1885, 366 (name 



only). 

 Tachisurus elatturus Eigeum. & Eigeiim. Proc. Cal. Acad. 2d Ser. 



vol. i, 1888, 142 (name only.). 

 Habitat: Panama. 



46. Tachisurus barbus, 



Pimelodus barbus Lacepede, Hist. Nat. Poiss. v, 94, 106, 1803. 

 Galeichthys barbus Jordan, Proc. U. S. Nat. Mus. 1886, 559 (name 



only). 

 Tachisurus barbus Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. vol. 



i, 1888, 142 (Campos; Kio Doce; Eio Grande do Sul). 

 Pimelodus commersonii Laceped, Hist. Nat. Poiss. v, 95, 108, pi. 3, 



fig. 1, 1803 (locality?). 

 Bagrus commersonii Valenciennes, in d'Orbigny, Voy. Amer. Merid. 



Poiss. Atlas ii, pi. 3, fig. 1, 1847; Cuvier & Valenciennes Hist. 



Nat. Poiss. xiv, 449, 1839 (Montevideo; Kio Janeiro); Kner, SB. 



Ak. Wien, xxvi, 1857, 386 (Kio Janeiro). 

 Arius commersonii Giinther, Cat. Fish. Brit. Mus. v, 143, 1864 



(Bahia); Hensel, Wiegm. Arch. 1870, i, 69 (Guahyba and larger 



tributaries); Steindachner, SB. Ak. Wien, Ixxiv, 1876, Siiss- 



wasserfische siidostlichen Brasiliens, iii, 85 (Bay of Kio Janeiro; 



Kio Grande do Sul; Kio Parahyba near Campos; Kio Doce; 



Santos). 

 Bagrus barbatus Quoy & Gaimard, " Voy. Uran. Zool. 230, pi. 49, 



figs. 1 and 2, 1824." 

 Pimelodus versicolor Castlenau, Anim. Amer. Sud, Poiss. 35, pi. 16, 



fig. 3 (Kio Araguay; Goyaz). 

 Habitat: Rio Plata and northward, ascending rivers. 



Body rather slender, little deeper than wide, the cau- 

 dal peduncle compressed. Head large, somewhat de- 

 pressed, its width 1J in its length, width at angle of the 

 mouth 2, its depth 1J. Interorbital area flattish, hav- 

 ing four obscure ridges in the old. Top of head coarsely 

 granular, the granules in series along the fontanel and 

 toward the eyes; opercles and occipital process smooth. 

 Occipital process J times as long as broad, sharply keeled 

 in the young. Fontanel 3J times as long as the eye, its 

 centre over the middle of the eye, continued as a groove 

 to the occipital process. 



Eye 2-2 in snout, 5|-8J in head, 3-4J in the inter- 

 ocular. 



