144 silurid^:. 



stronger and longer than that of the dorsal fin. Ventral fins much 

 shorter than the pectorals, not extending on to the anal. 



Brazil. 

 a, b. Bahia. Purchased of M. Parzudaki. 



8. Arius herzbergii. 



Silurus herzbergii, Bl. viii. p. 33. tab. 367 ; Bl. Schn. p. 382. 

 Bagrus herzbergii, Cuv. Sf Val. xiv. p. 453. 



coelestinus, Mull, fy Trosch. Hor. Ichth. iii. p. 7. 



mesops, Kner, Sitzungsber. Wien. Acad. p. 384. taf. 1. fig. 2 (not 



B. 6. D. 1/7. A. 18-20. P. 1/10. 



The height of the body is one-sixth of the total length (without 

 caudal), the length of the head two-sevenths. 

 Vomerine and palatine teeth confluent, the vo- 

 merine forming a subquadrangular patch, the pa- 

 latine a rather short, broad band which is notched 

 posteriorly. Six barbels : those of the maxillaries -\ ( \ / 

 extend to, or nearly to, or beyond the end of, 

 the pectoral fin, the outer ones of the mandible to, or nearly to, its 

 root. Head much depressed, much broader than high, its greatest 

 width being equal to its length without snout ; 

 its upper surface is granulated; occipital pro- 

 cess large, triangular, nearly as long as broad, 

 joining the basal bone of the dorsal spine, which 

 is small, crescent-shaped. Dorsal spine mode- 

 rately strong, half as long as the head, or a little 

 more than half as long, slightly serrated. Base 

 of tbe adipose fin as long as that of the dorsal. 

 Pectoral spine stronger and longer than that of the dorsal fin, ser- 

 rated on both edges. Ventral fins much shorter than the pectorals, 

 not extending on to the anal. 



Cayenne, Surinam, Para, "West Indies. 



a. Fine specimen. South America. From Sir K. Schomburgk's 



Collection. 



b. Young. British Guiana. Presented by Sir R. Schomburgk. 



c. Adult. Demerara. Purchased of Mr. Scrivener. 



d-e. Adult : stuffed. Demerara. Purchased of Mr. Scrivener. 



The typical specimens of S. herzbergii, Bl., and of B. coelestinus, 

 M. & T., are in the Berlin Museum ; Prof. Peters, who has examined 

 them, does not consider them as distinct species. 



9. Arius dubius. 



Netuma dubia, Bleek. Versl. en Mededeel. Acad. Wet. Amsterd. 1862, 

 xiv. p. 382. 



B. 6. D. 1/7. A. 19. P. 1/10. 



Closely allied to A. herzbergii. 



The height of the body is contained five times and three-fifths or 



