372 



SILUEIDJE. 



extending as far back as the occipito-nuchal process. Skin smooth, not villose. 

 Dorsal fin with I 7 rays, the spine strong, feebly serrated behind, striated in front, 

 as long as the head, with a filamentous prolongation exceeding it in length. Adipose 

 dorsal fin four and a half times as long as deep, twice as long as its distance from the 

 rayed dorsal. Anal fin rounded, with 11 rays, 7 of which are branched. Pectoral 

 spine nearly as long as the head, moderately serrated on the outer edge, very strongly 

 (15 serrae) on the inner, not reaching the ventral fin. Latter rounded, not reaching 

 the anal. Caudal fin deeply forked, upper lobe the longer. Caudal peduncle 

 as long as deep. 



Greyish above, with small scattered darker spots, white beneath ; fins whitish with 

 small greyish spots on the dorsal and caudal fins ; dorsal filament and upper and lower 

 borders of caudal fin black ; barbels white. 



A single specimen, anomalous in having the left maxillary barbel forked, was 

 procured by Mr. Loat at Jebelain *, White Nile, on January 10th, 1901. 



9. SYNODONTIS SERRATUS. 

 (Plate LXX. and Plate LXXI. fig. 2.) 



Riippell, Beschr. n. Fische Nil, p. 8, pi. ii. fig. 1 (1829) ; Cuvier & Valenciennes, Hist. Poiss. xv. 



p. 263 (1840) ; Giinther, Cat. Fish. v. p. 212 (1864), and Petherick's Trav. ii. p. 234 (1869) ; 



Vaillant, N. Arch. Mus. (3) viii. 1896, p. 136. 

 Pseudosynodontis serratus, Bleeker, Nederl. Tijdschr. Dierk. i. 1863, p. 55. 



Body moderately compressed, its depth three and one-fourth to four and one-fourth 

 times in the total length, the length of the head three and one-third to four and one- 

 third times. Head once and one-third to once and a half as long as broad, not or but 

 little broader than deep, more or less rugose above, behind the snout, the rugosities 

 sometimes concealed under a rather thick skin ; snout rounded or obtusely pointed, 

 longer than the postocular part of the head ; frontal fontanelle rather large ; eye 

 superolateral, its diameter five (young) to eleven times in the length of the head, 

 twice to four times in the width of the interorbital region, which is more or less 

 convex ; occiput very convex. Mouth with moderately developed lips ; praemaxillary 

 teeth forming a short and broad band ; movable mandibular teeth not half the 

 diameter of the eye, 30 to 48 in number. Maxillary barbel with a broad marginal 

 membrane in its proximal third, two-thirds to once and one-third the length of the 

 head, reaching between the base and the middle of the pectoral spine ; outer 

 mandibular barbel inserted a little further back than and about twice as long as the 



* Through a confusion of labels, the specimen was stated, in the original description, to be from the 

 mouth of Lake No, which is further south. 



