360 silueid^:. 



tubercular ramifications. Occipito-nuchal shield rough like the occiput, obtusely 

 tectiform, once and one-third to once and a half as long as broad, with pointed or 

 truncated posterior processes. Humeral process a little longer than broad, flat or with 

 a very obtuse keel, sharply pointed, usually not extending as far as the occipito-nuchal 

 process. Skin smooth, without villosities. Dorsal fin with I 7 rays, the spine strong, 

 feebly curved, three-fourths to once the length of the head, rather strongly serrated 

 behind, smooth in front, the soft terminal part produced into a short filament. Adipose 

 dorsal fin twice and a half to four times as long as deep, three to four and a half times 

 as long as its distance from the rayed dorsal. Anal fin acutely pointed in front, the 

 first branched ray usually produced into a filament ; 12 or 13 rays, 8 or 9 of which are 

 branched. Pectoral spine as long as or a little shorter than the spine of the dorsal, not 

 reaching the root of the ventral fin, its outer border distinctly serrated in the young, 

 smooth or very feebly serrated in the adult, its inner edge with 9 (young) to 21 strong 

 serrse. Ventral fin acutely pointed and often produced into a short filament, reaching 

 the origin of the anal fin or beyond. Caudal fin deeply forked, the upper lobe longer 

 than the lower. Caudal peduncle deeper than long. 



Grey-brown to blackish above and below, the lips white ; young with the body and 

 the dorsal fins spotted with black, and with some whitish markings at the base of the 

 caudal fin ; in older specimens the spots are replaced by a multitude of minute 

 dots, which may persist in the adult; iris brown, or silvery below the pupil and 

 brownish above. 



Total length 320 millim. 



Originally described from a specimen from the White Nile, received by the Paris 

 Museum from M. d'Arnaucl (Arnaud Bey) in 1843, this species has since been found at 

 various points on the White Nile, the Bahr-el-Gebel, the Victoria Nile, the Omo River, 

 and Lake Rudolf. 



The above description is drawn up from twenty-six specimens from the following 

 localities : — 



2 Goz abu Grumab. — Loat, 7.1.01. 

 2 Gharb-el-Aish.— Loat, 16.1.01. 



2 Fashoda.— Loat, 18-19.1.01. 



4 Between Khartum and the Sobat. — Zaphiro, 1904. 

 1 Bahr Zeraf.— Capt. Flower, 1.3.00. 



5 Mouth of L. No.— Loat, 1-8.10.01. 



3 Gondokoro.— Loat, 21.1-16.2.02. 



1 Fajao, Victoria Nile.— Budgett, 25.8.02. 



1 Omo River. — Dr. Donaldson Smith, 1900. 



5 Lake Rudolf at Graleba, 1800 feet.— Zaphiro, 7.8.05. 



In comparing the description here given with that published by Prof. Vaillant, it 



