On neio Fishes from the Nile System. GOl 



for a distinct species when compared with any published 

 description, which leads to the conclusion that differences of 

 outline in this part alone cannot properly be used to distin- 

 g;uish species ; and the same may be said of the dorsal hind 

 margins of the body-segments. 



LXXIL — Descriptions of Two new Fishes from the Nile 

 System, By G. A. Boulenger, F.R.S. 



(Published by permission of the Trustees of the British Museum.) 



A COLLECTION of fishcs recently made by Mr. F. J. Jackson, 

 C.B., in Uganda^ and presented by him to the British 

 Museum, includes examples of two new species, one of which 

 belongs to a genus which was not previously represented in 

 the fauna of the Nile system. 



Alestes jacksonii. 



Depth of body 3 times in total length, length of head 4 

 times. Head twice as long as broad, slightly longer than 

 deep ; snout rounded, as long as the eye, which is lateral 

 and 3| times in length of head ; iuterorbital region, feebly 

 convex, its width 2| times in length of head ; maxillary 

 nearly reaching to below anterior border of eye ; 16 teeth 

 (I) in upper jaw, 10 (|) in lower ; lower border of second 

 suborbital as long as eye. Gill-rakers moderately long, 16 

 on lower part of anterior arch. Dorsal II 8, originatiuo- 

 just behind vertical of base of ventral, at equal distance 

 from eye and from caudal, longest ray as long as head. 

 Anal 111 15, pointed in the middle (male). Pectoral nearly 

 as long as head, reaching ventral. Caudal deeply forked, 

 lobes pointed. Caudal peduncle a little longer than deep. 

 Scales with radiating and anastomosing canals, 26 ||, 2 be- 

 tween lateral line and root of ventral. Silvery, brownish on 

 the back, with a rather indistinct dark lateral band from 

 above the gill-cover to the root of the caudal fin ; dorsal fin 

 greyish, other fins yellow. 



Total length 150 mm. 



A single specimen from the Malawa River, Kaviroudo, 

 4000 feet. 



Allied to A. affinis, Gtlir. 



