SOUTH AMERICAN NEMATOGNATHI. 59 



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

 Galeichthys j^assany Jordan, Proc. U. S. Nat. Mus. 1886, 559 (name 

 onlj') . 



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



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

 Habitat: Cayenne. 



32. Tachisurus albicans. 



Bayrus albicans Cuv. & Val. Hist. Nat. Poiss. xiv, 461, pi. 420, 18.39 



(Cayenne). 

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



only). 

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



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

 1 Bagrus Valencierinei Gasielnan, Anim. Amer. Sud, Poiss. 31, pi. xiii, 



fig. 1, 1855 (Amazons). 

 Arius valencicnnesii Giinther, Cat. Fish. Brit. Mus. v, 150, 1864 



(copied). 

 Habitat: Amazon and northward. 



33. Tachisurus herzbergii. 



Silurus herzberfjii Bloch, Ausl. Fisch. iJart 8, .3.3, pi. .367 (Surinam); 



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

 Bagrus herzbergii Cuv.& Val. Hist. Nat. Poiss. xiv, 45,3, 1839 (Mana, 



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

 Selenaspis herzbergii Bleeker, Ichth. Arch. Ind. Prodr. 1, 63. 

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



Guiana; Demerara). 

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



fig. 3, 1864 (Surinam). 

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



only). 

 Tachisurus herzbergii 'EAgennx. 8c 'Eigen-m. 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 ccelestinus Miiller & Troschel, Horse Ichth. iii, 7, 1849 



(Guiana). 

 Bagrus mesops Kner, SB. Ak. Wien, xxvi, 1857, 384, pi. i, fig. 2 



(Para), (not Bagrus mesojisG. & V.) 

 Hexanematichthys 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 li-lj in its length, at the angle of 

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



