432 SILUEIDJE. 



membrane, 1 to 1^ times length of head, reaching between base and 

 middle of pectoral spine ; outer mandibular barbel about twice as long 

 as inner, both with moderately long simple or more or less ramified 

 branches. Gill-opening not extending downwards beyond root of 

 pectoral spine. Occipito-nuchal shield rugose like the occiput, simply 

 convex or obtusely tectiform, 1 to 1^ times as long as broad, with 

 posterior processes pointed or rounded. Humeral process longer than 

 broad, granulate, feebly keeled, extending as far back as occipito-nuchal 

 process. Dorsal I 7 ; spine as long as or shorter than head, feebly 

 curved, striated, smooth in front, feebly serrated behind. Adipose 

 dorsal 3^ times as long as deep, 3 times as long as its distance from 

 rayed dorsal. Anal III 8, rounded. Pectoral spine as long as or 

 slightly shorter than head, not reaching ventral, strongly serrated on 

 outer border, still more so on inner. Ventral reaching anal. Caudal 

 deeply forked. Caudal peduncle as long as deep. Dark brown above 

 and beneath ; fins dark brown or black, with some light cross-bands in 

 the young. 



Total length 205 millim. 



Lower Niger, Lagos. 



20. SYXODONTIS MAOttOSTIGMA, sp. n. 

 Depth of body 3^ times in total length, length of head 3J to 3f times. 

 Head a little longer than broad, rugose above ; snout rounded and as 

 long as postocular part of head ; eye superolateral, 6 to fii times in 

 length of head, twice or a little over Uice in interorbital width; lips 

 moderately developed ; preemaxillary teeth forming a short and broad 

 band ; movable mandibular teeth not quite \ diameter of eye, 20 to 26 

 in number. Maxillary barbel with a broad marginal membrane behind 

 and a series of round warts in front, f length of head, just reaching base 

 of pectoral spine; mandibular barbels with short tubercular branches, 

 outer not quite twice as long as inner. Gill-opening not extending 

 downwards beyond root of pectoral spine. Occipito-nuchal shield rough 

 like the occiput, merely convex, as long as broad, posterior processes 

 rounded. Humeral process a little longer than broad, triangular, 



