PETEOGEPHALUS. 53 



10 or 12 round caudal peduncle. Brown above, silvery below ; a dark 

 spot at base of caudal, and another below origin of dorsal. 



Total length 170 millim. 



Ogowe, Congo. — Type in Paris Museum. 

 1. Ad. (Type o£ M. amhlystoma.) Talagouga, Ogowo. Miss Kingsley (C). 

 2-4. Ad. & hgr. Koinadekke, Ogowe. Dr. W. J. Ansorge (C). 



5. PETROCErHALUS SIMUS. 

 Sauv. Bull. Soc. Philom. (7) iii. 1878, p. 100 ; Boult-ng. Proo. Zoo). Soc. 1898, 



p. 789, and Poiss. Bass. Congo, p. 73 (1901) ; Pappenli. Mitth. Zool. Miis. 



Beil. iii. 1907, p. 344. 

 Mormyriis (Fetrocephalus) simus, Sauv. N. Arch. Mus. (2) iii. 1880, p. 51, 



pi. ii. fig. 3. 

 Mormi/rus tenuicamla, Steind. Notes Leyd. Mus. xvi. 1894, p. 69, pi. vi. fig. 1. 

 Mormyrus simiis, Giinth. Ann. & Mag. N. H. (6) xvii. 1896, p. 282. 



Depth of body 2| to o^ times in total length, length of head 3| to 4^ 

 times. Head as long as deep, with convex upper profile ; snout very 

 short, \ length of head, obliquely truncate, projecting beyond mouth ; 

 mouth below anterior border of eye, its width y to ^ length of head; 

 teeth bicuspid, 10-18 in upper jaw, 16-24 in lower ; nostrils near lower 

 border of eye ; eye rather large, a little longer than snout, f inter- 

 Fig. 38. 



PetrocepTidlvs sinnis. 

 Type, after Sauvage (N. Arch. Mus. 1880). 



orbital width. Dorsal 24-28, originating above 5th to 7th ray of anal, 

 its length 1^ to 2 times in its distance from head, and equal to or 

 slightly greater than its distance from caudal. Anal 30-34, equally 

 distant from base of ventral and from base of caudal. Pectoral pointed, 

 f length of head, twice as long as ventral, extending beyond base of 

 latter. Caudal scaled at the base, with pointed lobes. Caudal peduncle 



