120 siluridjE. 



angular, rather longer than broad, not reaching the basal bone of the 

 dorsal spine. Adipose fin very long, its length being contained twice 

 and a third in the total (without caudal) ; it commences at a very- 

 short distance from the dorsal. Maxillary barbels extending not 

 quite to the caudal fin, the outer ones of the mandible to, or beyond, 

 the extremity of the pectoral. 



The height of the body is contained five times and a half in the 

 total length (without caudal), the length of the head four times and 

 a quarter. The lower jaw is scarcely shorter than the upper ; the 

 band of intermaxillary teeth is about eight times as broad as long. 

 The diameter of the eye is one-half of the width of the interorbital 

 space. A small porus axillaris. Dorsal fin with the spine very feeble, 

 higher than long. Pectoral spine serrated along both edges, as long 

 as the head without snout. Caudal fin cleft to the base. Coloration 

 uniform ; dorsal fin with the usual whitish cross-band. 



Brazil, Surinam. 



a. Seven inches long. River Capin, Para. Purchased of Mr. Stevens. 



b. Young. Para. Presented by R. Graham, Esq. 



c. Half-grown. Surinam. Purchased of Mr. Frank. 



10. Pimelodus holomelas. 

 D. 1/6. A. 9-10. P. 1/8. V. 6. 



Head covered with skin above ; occipital process triangular, con- 

 siderably longer than broad, not reaching the basal bone of the 

 dorsal spine. Adipose fin very long, its length being contained twice 

 and a fourth or twice and a fifth in the total (without caudal) ; it 

 commences at a short distance from the dorsal. Maxillary barbels 

 extending beyond the commencement, or to the middle, of the adipose 

 fin, the outer ones of the mandible to the middle of the pectoral. 



The height of the body is contained five times and a half or five 

 times and two-thirds in the total length (without caudal), the length 

 of the head four times. The lower jaw is distinctly shorter than the 

 upper ; the band of intermaxillary teeth is seven times as broad as 

 long. The diameter of the eye is one-half of the width of the inter- 

 orbital space. No porus axillaris. Dorsal fin with the spine very 

 feeble, scarcely higher than long. Pectoral spine serrated along both 

 edges, as long as the head without snout. Caudal fin cleft to the 

 base. Uniform black, with a brownish shade, somewhat lighter on 

 the belly. 



Essequibo. 



a-d. Adult (12 inches long) and young. From Mr. Ehrhardt's Col- 

 lection. 



This species is closely allied to P. mulleri, but may be distinguished 

 by a longer adipose fin, shorter barbels, longer head, lower dorsal fin, 

 and by its dark colours. 



