GNATHONEMUS. 57 



and of which he only saw a sketch, belonged to this species rather than to Gnathonemus 

 petersii, Gthr., a very closely allied species with a similar mental appendage, but in 

 which the dorsal and anal rays are more numerous (D. 27-29, A. 34-36) and the 

 scales generally more numerous along the lateral line (63-70). G. petersii has been 

 found in the Congo and Ubanghi, the Old Calabar, and the Niger Delta. 



Except for the longer snout and the curious mental appendage, G. longibarbis 

 resembles very closely the following species. 



5. GNATHONEMUS NIGER. 

 (Plate X. fig. 3.) 



Mormyrus niger, Giinther, Cat. Fish. vi. p. 219 (1866). 

 Gnathonemus niger, Boulenger, Proc. Zool. Soc. 1898, p. 802. 



Body strongly compressed, its depth three and one-fifth to three and five-sixths 

 times in the total length ; length of head four and one-third to five and one-fourth 

 times in the total length. Head as long as deep, nearly twice as long as broad, with 

 curved upper profile ; snout very short, rounded, as long as the eye, five to six and 

 a half times in the length of the head; interorbital width once and three-fourths or 

 twice the diameter of the eye ; mouth small, on a line with the lower border of the 

 eye ; no mental swelling; teeth small, notched, 5 in the upper jaw, 8 or 10 in the 

 lower. Dorsal fin with 17 to 20 rays, originating above the eighth to the tenth ray of 

 the anal, its length twice to three times in its distance from the head. Anal fin with 

 25 to 28 rays, nearer to the root of the caudal then to the base of the ventral ; both 

 fins deepest in front, especially the anal of the males, the base of which is sinuous. 

 Pectoral fin pointed, falciform, a little longer than the head, at least twice as long as 

 the ventral and extending nearly or quite to the extremity of the latter. Caudal fin 

 scaly in its basal third, with obtusely pointed lobes. Caudal peduncle two-thirds to 

 four-fifths the length of the head, about twice as long as deep. 51 to 58 scales in the 

 lateral line, ^^s in a transverse series on the body, -g^ in a transverse series between 

 dorsal and anal fins, 12 round caudal peduncle. 



Specimens preserved in spirit are silvery, more or less speckled with dark brown, 

 the back dark brown. 



Not known to exceed a length of 125 millim. 



The types of this species came from the Gambia and the Niger. Six specimens 

 were obtained at Fashoda by Mr. Loat during the second half of March 1901, and 

 four at Polkom, on the Baro River (Sobat), by Mr. Zaphiro in April 1904 (presented 

 to the British Museum by Mr. W. N. McMillan). 



i 



