SOUTH AMERICAN NEMATOGNATHI. 59 



Arius passany Gitnther, Cat. Fish. Brit. Mus. v, 149, 1864 (copied). 

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



only). 

 Tachisurus passany Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. 



vol. i, 1888, 141 (name only). 

 Habitat: Cayenne. 



32, Tachisurus albicans. 



Bagrus albicans Cuv. & Val. Hist. Nat. Poiss. xiv, 461, pi. 420, 1839 



(Cayenne). 

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



only.) . 

 Tachisurus albicans Eigeiiin. & Eigenm. Proc. Cal. Acad. 2d Ser. 



vol. i, 1888, 141 (name only). 

 ? Bagrus ralencienneiCsLsieluem, Anim. Arner. Sud, Poiss. 31, pi. xiii, 



fig. 1, 1855 (Amazons). 

 Arius valenciennesii ( Giinther, Cat. Fish. Brit. Mus. v, 150, 1864 



(copied). 

 Habitat: Amazon and northward. 



33, Tachisurus herzbergii, 



Silurus herzbergii Bloch, Ausl. Fisch. part 8, 33, pi. 367 (Surinam); 



Bloch & Schneider, Syst. Ichthyol. 383, 1801 (Surinam). 

 Bagrus herzbergii Cuv. Val. Hist. Nat. Poiss. xiv, 453, 1839 (Mana, 



Cayenne); Kner, SB. Ak. Wien, xxvi, 1857, 386 (Para). 

 Selenaspis herzbergii Bleeker, Ichth. Arch. Ind. Prodr. i, 63. 

 Arius herzbergii Giinther, Cat. Fish. Brit. Mus. v, 144, 1864 (British 



Guiana; Demerara). 

 Netuma herzbergii Bleeker, Silures de Suriname, 61, pi. ix, pi. xiii, 



fig. 3, 1864 (Surinam). 

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



only). 

 Tachisurus herzbergii Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. 



vol. i, 1888, 141 (Para; Curuca; Bahia). 



Pimelodus argenteus Lacepede, Hist. Nat. Poiss. v, 94 and 102, 1801. 

 Bagrus pemecus Cuvier & Valenciennes, xiv, 456, 1839 (Cayenne). 

 Bagrus ccelestmus Miiller & Troschel, Horse Ichth. iii, 7, 1849 



(Guiana). 

 Bagrus mesops.~K.ner, SB. Ak. Wien, xxvi, 1857, 384, pi. i, fig. 2 



(Para), (not Bagrus mesops C. & V.) 

 ffexanematichthys hymenorhinus Bleeker, Silures de Suriname, 57, 



pi. xi, fig. 2, pi. xiii, fig. 4, 1864 (Surinam). 

 Habitat: From Para northward. 



Elongate, the width as great or greater than the depth. 

 Width of the head 14-1 J- in its length, at the angle of 

 the mouth about 2; depth If-lf in its length. Humeral 



