MOCHOCUS. 493 



Pectoral fin with a strong spine ; ventral fin with 7 rays. A cephalo- 

 nuchal bony shield. Mouth subinferior, small, without labial folds ; 

 small conical teeth in both jaws, none on the palate. A maxillary and 

 two mandibular barbels on each side, the latter branched. Nostrils 

 rather remote from each other, both with a valve, the posterior very 

 large. Eye moderate, without free border. Gill-openings small, con- 

 fined to the sides. Air-bladder large, free. 



Vertebra 33-34 (11 + 22-23). 



Nile and Lake Rudolf. 



Two species : — 



First dorsal fin much nearer end of snout than 



root of caudal, with the spine serrated in 



front and with 7 or 8 soft rays 1. M. niloi'icus^ Joann., p. 493. 



First dorsal fin nearly equally distant from end 



of snout and from root of caudal, with the 



spine smooth in front and with G soft rays . 2. M. hrev'is, Blgr., p. 495. 



1. MOCHOCUS NILOTICUS. 



Joaniiis, 1. c. pi. \iii. ; Giinth. ]. c, and Petherick's Trav. ii. p. 239 (18G9) ; 



Bouleng. 11. cc. pi. Ixxvi. p. 2. 

 RIdnoglanis ti/piis, Giinth. 11. cc. pp. 216, fig., and 237, fig. 

 Jiliinaglanis vannutellii, Vincig. Ann. Mus. Genova, (2) xix. 1898, p. 254. 



Depth of body 4|- to 5§ times in total length, length of head 3|- to 

 4-|- times. Head depressed, not or but little longer than broad, rugose 

 above, with a large, oval frontal fontanelle ; occiput with a low, blunt 

 keel, which is continued on the nuchal shield ; eye supero-lateral, 3 to 

 4|- times in length of head, 1\ to 1^ times in interorbital width. 

 Barbels long and slender, maxillary 1^ to 2-^ times as long as head, 

 reaching posterior third of pectoral spine, base of ventral, or a little 

 beyond ; mandibular barbels shorter, with a few slender simple branches. 

 Occipito-nuchal shield as long as broad or longer than broad, with short, 

 rounded posterior processes. A long pointed humeral process. Anterior 

 dorsal I 7 (rarely 8), much nearer end of snout than root of caudal ; 

 spine as long as or a little shorter than head, finely serrated in front ; 

 second dorsal with 10-15 rays, preceded by a few fulcra-like bony 

 scutes, as long as or a little longer than its distance from the first. A 

 series of three or four small bony scutes, ankylosed to the interneural 

 bones, on each side of soft part of first dorsal fin. Anal 9-10. Pectoral 

 spine as long as or a little longer tluin that of dorsal, finely serrated on 



