76 CALIFORNIA ACADEMY OF SCIENCES. 



Oaleichthys elatturus Jordau, Proc. U. S. Nat. Miis. 1885, 366 (name 



only). 

 Tachisurus elatturus Eigenm. & Eigeum. 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. 

 Galeichthyn 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; Kio Grande do Sul). 

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



fig. 1, 1803 (locality?). 

 Baijrus 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); Kuer, SB. 



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

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



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



tribvitaries); Steindachner, SB. Ak. Wien, Ixxiv, 1876, Sixss- 



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



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



Santos). 

 Bagrus barbatus Quoy & Gaimard, "Voy. Uran. Zool. 2.30, pi. 49, 



figs. 1 and 2, 1824." 

 Pimelodus versicolor Castlenau, Auim. Amtir. Sud, Poiss. 35, pi. 16, 



fig. 3 (Kio Araguay; Goyaz). 

 Habitat: Kio Plata and northward, ascending rivers. 



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

 dal jDeduncle compressed. Head large, somewhat de- 

 pressed, its width Ij in its length, width at angle of the 

 mouth 2, its depth li, 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 | times as long as broad, sharply keeled 

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

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

 to the occipital process. 



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

 ocular. 



