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. nilotieus, 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 6 soft rays . 2. M. brevls, Blgr., p. 495. 



1. MOCHOCUS NILOTICUS. 



Joannis, 1. c. pi. viii. ; Gunth. 1. c, and Petherick's Trav. ii. p. 239 (1869) ; 



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

 Rhinoglanis typns, Gunth. 11. cc. pp. 216, fig., and 237, fig. 

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



Depth of body 4-g- to 5f 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 than that of dorsal, finely serrated on 



