SYNODONTIS. 397 



Maxillary barbel not more than i length oE 

 head ; movable mandibular teeth at least 



as long as eye 51. S. sorex, Gthr., p. 465. 



b. Eyes perfectly lateral, visible from below as well as from above ; 

 movable mandibular teeth 12-19 ; adipose dorsal shorter than head. 

 Maxillary barbel shorter than head .... 52. S. pleurops, Blgr., p. 466. 

 II. Maxillary barbel branched ; gill-opening not extending downwards beyond 

 base of pectoral spine. 

 Movable mandibular teeth 4-11 ; maxillary 

 barbel not margined, with short branches ; 

 adipose dorsal as long as its distance from 



l'ayed dorsal 53. S. decorus, Blgr., p. 468. 



Movable mandibular teeth 6-9 ; maxillary 

 barbel with a distinct marginal membrane 

 at base and with long, slender, finely 

 tuberculate branches ; adipose dorsal much 



longer than its distance from rayed dorsal. 54. S. clarias, L., p. 469. 

 Movable mandibular teeth 60 ; maxillary 

 barbel with a broad marginal membrane 

 and short, obtuse branches ; adipose dorsal 



nearly touching rayed dorsal 55. S. resupinatus, Blgr., p. 471. 



III. Maxillary barbel not branched, but broadly margined ; gill-opening extend- 

 ing downwards beyond base of pectoral spine ; adipose dorsal touching 

 rayed dorsal. 

 Gill-openings widely separated ; mandibular 

 barbels branched but not margined ; 



movable mandibular teeth 30-57 . . .56. S. batensoda, Riipp., p. 472. 

 Gill-openings separated by a narrow isthmus ; 

 mandibular barbels branched at the base, 



with a membranous margin at the end ; [p. 474. 



movable mandibular teeth 6-9 .... 57. S. membranaceus, Geoffr., 



1. 8YNODONTIS CAUDALIS. 

 Bouleng. Ann. Mus. Congo, Zool. i. p. 44, pi. xxii. fig. 1 (1899), and Poiss. Bass. 

 Congo, p. 306 (1901). 



Depth of body equal to length of head, 4 to 4^ times in total length. 

 Head as broad as long, nearly smooth above ; snout rounded, | length 

 of head ; eye supero-lateral, 5^ to 6 times in length of head ; 2 to 2^ 

 times in interorbital width ; lips much developed ; pramaxillary teeth 

 forming a rather long and moderately broad band ; movable mandibular 

 teeth hardly ^ diameter of eye, 70 to SO in number. Maxillary barbel 

 not margined, lh to 1| times length of head ; mandibular barbels with 



