258 CHAEACINID.E. 



U. DISTICHODUS. 



Miill. & Trosch. Hor. Ichthyol. i. p. 12 (1845) ; Cuv. & Val. Hist. Poiss. xxii. 

 ]<. 172 (1849) ; Gunth. Cat. Fish. v. p. 359 (1864) ; Bouleng. Poiss. Bass. 

 Congo, p. 185 (1901), and Fish. Nile, p. 139 (1907). 



Snout moderate or short ; mouth small, inferior or subinferior, with 

 small bicuspid teeth, usually forming two series in each jaw; maxillary 

 toothless, moderately large. Cheek covered by the suborbitals ; nostrils 

 close together, separated by a valvular flap ; gill-membranes attached to 

 isthmus. Body short or moderately elongate, strongly compressed. 

 Scales moderate or small, strongly ciliated ; lateral line straight, equally 

 distant from the dorsal and the ventral outlines, or nearer the former; 

 a scaly process at base of ventral fin. Dorsal fin with 16 to 27 rays, 

 above the ventrals ; anal fin with 11 to 21 rays; a small or moderately 

 large adipose dorsal fin. Vertebrae 41-51 (26-33 + 15-18), 



Small scales cover the whole or the greater part of the caudal and 

 adipose fins. 



Nile and Tropical Africa. 



Synopsis of the Sjyecies. 



I. Scales 37-57 '^' ^ ; D. lG-20; snout broad or feebly compressed. 



A. Base of anal at least as long as that of dorsal, which equals its distance 



from adipose fin ; lobes of caudal short and rounded. 

 A. 19-21 ; So. 37-39 ^, 7 between lateral line 



and ventral 1. D. affinis, Gthr., p. 260. 



A. 21-22 ; Sc. 40-42 j^, 9 between lateral 



line and ventral 2. D. alius, Blgr., p. 261. 



B. Base of anal shorter than that of dorsal. 

 A. 16 ; Sc. 45 T^, 8 between lateral line and 



ventral ; lobes of caudal rounded . . . 3. Z*. noboli, Blgr., p. 262. 

 A. 14-16 ; Sc. 38-46 ^, 6-7 between lateral 



line and ventral ; lobes of caudal pointed . i. D. notospilus, Gthr., p. 262. 

 A. 12-13 ; So. 53-57 ttttT' ^ between lateral 



line and ventral ; lobes of caudal obtusely [p. 264. 



pointed 5. D. hjpostomatus, Pellegr., 



II. Scales 60-110 ^^. 



A. Snout deeper than long, broad or feebly compressed, 

 cales 60-85 ' ^- , 

 D. 16-19 ; A. 11 



1. Scales 60-85 ,., ° , 9-14 between lateral line and ventral. 



