SOUTH AMERICAN NEMATOGNATHI. 57 



toothed in front, roughened behind; distance of adipose 

 fin from the dorsal 3J in the length; the adipose fin 

 much longer than high; as long as the dorsal fi 



Caudal fin 5 in the length. 



Anal scarcely longer than high. 



Ventrals reaching almost to the anal, 2J i 



Pectoral spine If in head, its outer edge 

 toothed, the inner with very fine teeth. 



No axillary pore; no vertical series of pores. 



Head brownish with purple reflections, the body 

 metallic blue above with greenish reflections, silvery 

 below, the sides and region about the veiitrals thickly 

 covered with brown dots; fins all dusky. 



Head 3^; depth 4f ; D. I, 7; A. 18.' 



A single specimen .52 m. Panama. One of the 

 types. 



29, Tachisurus mesops, 



Bayrus mesops Cuv. & Val. Hist. Nat. Poiss. xiv 456, 1839, (Guiana.) 

 Arius mesops Giinther, Cat. Fish. Brit. Mus. v, 145, 1864 (copied). 

 Oaleichthys mesops Jordan, Proc. U. S. Nat. Mus. 1886, 559 (name 



only). 

 Tachifiurus mesops Eigenm. & Eigenm. Proc. Cal. Acad. 2d. Ser. vol. 



i, 1888, 141 (name only). 

 Habitat: Guiana. 



30, Tachisurus proops 



Bagrus proops Cuv. & Val. Hist. Nat. Poiss. xiv, 457, 1839 (Antilles; 



Guiana; Surinam; Porto Kico); Kner, SB. Ak. Wien, xxvi, 



1857, 386 (loc. ?) 



Arius proops Giinther, Cat. Fish. Brit, Mus. v, 148, 1864 (copied). 

 Netuma proops Bleeker, Ichth. Arch. Ind. Prod, i, 67; Bleeker, 



Silures de Suriname, 62, pi. vii, pi. xii, fig. 2, 1864 (Surinam). 

 Gakichthys proops Jordan, Proc. U. S. Nat. Mus. 1886, 559 (name 



only). 

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



vol. i, 1888, 141 (Pernambuco). 

 Habitat: Northern coast of South America to Pernambuco. 



Slender and elongate, broader than deep. Head de- 

 pressed, its width 1J in its length, its depth 2, width at 

 mouth 2; anterior portion of the head flat above; top of 

 the head, humeral process, and dorsal plate, coarsely 



