STNODONTIS. 401 



the occiput, If to H times as long as broad, with truncate or pointed 

 posterior processes. Humeral process 2\ to 3 times as long as broad, 

 extending as far back as occipito-nuchal shield, armed in the adult with 

 several strong spines directed backwards ; these spines reduced to 2 or 

 3 in the young. Skin villose on the sides. Dorsal I 6-7 ; spine as long 

 as or a little shorter than head, striated, smooth in front, very feebly 

 serrated behind. Adipose dorsal 5 to 7 times as long as deep, 3 to 5 

 times as long as its distance from rayed dorsal. Anal IV 8-10, rounded 

 or obtusely pointed in front. Pectoral spine a little longer than head, 

 strongly serrated on both sides. Ventral reaching anal or not. Caudal 

 deeply forked, upper lobe the longer. Caudal peduncle as long as deep. 

 Greyish or brownish above, uniform or with small round blackish spots, 

 yellowish white beneath. 



Total length 400 millim. 



Congo. — Types in Congo Museum, Tervueren. 



1. One of the types. Boma, Lower Congo. Capt. Wilverth (C). 



2. Ad. Matadi, „ M. P. Delhez (C). 



3. Ad. Stanley Pool. M. De Meuse (C). 

 4-5. Ad. & hgr. Monsembe, Upper Congo. Rev. J. H. Weeks (P.). 

 6. Ad. Stanley Falls. Rev. W. H. Bentley (C). 

 7-10. Ad. & hgr. Upper Congo. Brussels University. 



11. Skel. „ Rev. G. Grenfell (P.). 



4. SYNODONTIS OMIAS. 

 Giintb. Cat. Fish. v. p. 213 (18(54) ; Bouleng. Poiss. Bass. Congo, p. 311 (1901). 



Depth of body equal to length of head, o\ times in total length. 

 Head a little longer than broad, feebly rugose above from between the 

 eyes ; snout very obtusely pointed, as long as or slightly shorter than 

 postocular part of head ; eye supero-lateral, 5 to 6 times in length of 

 head, 2 to 1\ times in interorbital width; lips moderately developed; 

 pra?maxillary teeth forming a broad and short band ; movable mandibular 

 teeth barely f diameter of eye, 40 to 50 in number. Maxillary barbel 

 with a rudiment of fringe at base, a little longer than head, reaching 

 anterior third of pectoral spine ; mandibular barbels with short branches 

 bearing tubercular ramifications, outer twice as long as inner. Gill- 

 openings not extending downwards beyond root of pectoral spine. 

 Occipito-nuchal shield obtusely tectiform, feebly rugose like the 

 occiput, \\ to \\ times as long as broad, with rounded or truncate 

 posterior processes. Humeral process \\ times as long as broad, 



VOL. II. 2d 



