M OEM YE ID ^. 



4. PETROOEPHALUS BALLAYI. 

 Morimjrns catostoma (non Giinth. 18G6), Giinth. Ann. & Mag. N. H. (3) xx. 18G7, 



p. 166. 

 Petrocephalus halayi, Sanv. Bull. Soc. Pliilom. (7) vii. 1883, p. 159 ; Boulong. 



Proc. Zool. Soc. 1898, p. 789, and Poiss. Bass. Congo, p. 72 (1901) ; Pellegr. 



Bull. Soc. Philom. (9) ix. 1907, p. 20. 

 Mormyrus amllystoma, Gunth. Ann. & Mag. N. H. (G) xvii. 1896, p. 281, 



pi. xiv. fig. A. 



Depth of body 2f to 3 times in total lenyth, length of head 3| to 

 3f times. Head as lung as deep, with convex upper profile ; snout very 

 short, ^ to y length of head, obliquely truncate, projecting beyond mouth ; 

 mouth below anterior border or centre of eye, its width ■§■ length of head ; 

 teeth bicuspid, 20-24 in upper jaw, 30-36 in lower; nostrils above 

 lower border of eye ; eye large, its diameter greater than length of 

 snout, I interorbital width. Dorsal 2] -25, originating above 4th or 5th 

 ray of anal, its length nearly J its distance from head and equal to its 



Fig. 37. 



f 



X 



f 



PefroeejiJialus ballai/i. 

 Type of M. ambli/stoma, after Giintlier (Ann. & Mag. N. H. 1896). 



distance from caudal. Anal 28-30, slightly nearer base of caudal than 

 base of ventral. Pectoral pointed, f length of head. If length of 

 ventral, extending beyond base of latter. Caudal scaled at the base, 

 with pointed lobes. Caudal peduncle 2^ to 3 times as long as deep, 

 I to I length of head. 35-37 scales in lateral line, ^^ in transverse 

 series on the body, ^ in transverse series between dorsal and anal, 



