1, N0T0PIERU8, 481 



hones of the head are serrated, except the intero-inferior edge of the 

 pra2operculum.^ Nasal appendage very distinct. 



There are nine stout gill-rakera along the lower branch of the 

 outer branchial arch. Forty pairs of spines along the abdomen. 

 No trace of ventrals. Dorsal fin considerably nearer to the end of 

 the snout than to that of the tail, opposite to the twenty-fourth anal 

 ray. Pectoral fin extending to or a little beyond the origin of the 

 anal fin. Scales very small. Unifoi'ra brown, or brownish black, 

 sometimes with more or less numerous light-reddish spots. 



West Africa. 



a-h. Half-growh fine specimens. Sierra Leone. Purchased of Mr. 



Stevens. 

 c, d. Adult (18 inches long) and half-grown. West Africa. 

 e~f. Half -grown : skins. West Africa. Purchased of Mr. Dalton. 



/3. Xenomystus. 



5. Notoptems nigri. 

 B. 3. D. 0. A-f-C. 113. 



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

 total length (with the caudal), the length of the head six times and 

 two-thirds. Upper profile of the head and neck slightly convex. 

 The diameter of the eye is more than the length of the snout, and 

 two-sevenths of that of the head. The mrxillary does not extend 

 to below the middle of the orbit. Teeth in the jaws in a single 

 series ; palatine and sphenoid teeth in an extremely narrow band. 

 Nasal appendages rather long, forming a pair of barbels as long as 

 the snout. Suborbital ring and lower edges of the mandible and 

 praeoperculum serrated. Gill-membranes rather broadly united. 

 Twenty-one pairs of spines along the abdomen. Ventral fins ex- 

 tremely small. Pectoral fins nearly as long as the head, reaching 

 far beyond the origin of the anal fin. Scales very small. Uniform 

 brown. 



River Niger. 



<i. Six inches long. From Mr. Fraser's Collectian. 



