PETROCEPHALUS.— ISICHTHTS. 59 



originating above first ray of anal, its length twice and ^ in its distance 

 from head. Anal 27, equally distant from base of ventral and from base 

 of caudal. Pectoral pointed, about § length of head, twice as long as 

 ventral, and extending beyond vertical of base of latter. Caudal fin with 

 pointed lobes. Caudal peduncle twice and •§• as long as deep, f length 

 of head. 41 scales in lateral line, ^ in transverse series on body, § in 

 transverse series between dorsal and anal, 12 round caudal peduncle. 

 Silvery ; back dark grey ; fins grey. 



Total length 88 millim. 



Lake Victoria. 

 1. Type. Mouth of Katonga R. Mr. E. Degen (0.). 



3. ISICHTHYS. 

 Gill, Proc. Ac. Pliilad. 18G2, p. 444 (1863) ; Bouleng. Proc. Zool. Soc. 1898, 



p. 791. 

 Mormyrops, part,., Gunth. Cat. Fish. vi. p. 223 (1866). 



Teeth rather large, notched, few, 5-6 in the upper jaw, 6 in the 

 lower; minute conical teeth on the parasphenoid and on the tongue ; 

 mouth subinferior, below the level of the eye. Nostrils widely separated. 

 Body much elongate ; ventrals much nearer anal than pectorals. Dorsal 

 a little longer than anal. Vertebrae 64 (26 + 3s). 



West Africa. 



1. ISICHTHYS HENRYI. 



Gill, Proc. Ac. Philad. 1862, p. 444 ; Bouleng. Proc. Zool. Soc. 1898, p. 791 ; 



Pappenh. Mitth. Zool. Mus. Berl. iii. 1907, p. 347. 

 Mormyrops henryi, Gunth. Cat. Fish. vi. p. 224 (1866) ; Hubrecht, Notes Leyd. 



Mus. iii. 1881, p. 70. 

 Mormyrus henryi, Gunth. Ann. & Mag. N. H. (3) xx. 1867, p. 115 ; Steiud. Notes 



LeyJ. Mus. xvi. 1894, p. 66. 

 Mormymis cobitiformis, Peters, Sitzb. Ges. nat. Fr. Berl. 1882, p. 72. 

 Mormyrus (Isistius) henryi, S;iuvage, Bull. Soc. Zool. France, 1884, p. 207, pi. vi. 



fig- 1. 

 Depth of body 8 to 11 times in total length, length of head 6 to 1\ times. 

 Head If to 2 times as long as deep ; snout rounded, \ to \ length of head ; 

 mouth subinferior, its width \ length of head ; nostrils midway between 

 eye and end of snout; eye small, hardly \ length of snout, -g- inter- 

 orbital width. Dorsal 39-50, longer than its distance from head. Anal 

 38-47, originating a little posterior to origin of dorsal. Pectoral about 



