352 SILTJRID.E. 



2. Maxillary barbel broadly margined, the marginal membrane, at the base, at least nearly 

 as broad as the barbel. 



a. Snout not longer than postocular part of head ; spine of dorsal fin not distinctly 



serrated in front. 



30 to 35 movable mandibular teeth ; adipose dorsal fin not more 

 than twice as long as its distance from the rayed dorsal ; 

 humeral process pointed 6. & nigrita, C. & Y. 



45 to 50 movable mandibular teeth ; adipose dorsal fin six times 

 as long as its distance from the rayed dorsal fin, the anterior 

 rays of which are much produced ; humeral process obtuse- 

 pointed 7. & eupterus, Blgr. 



20 movable mandibular teeth ; adipose dorsal fin three times as 

 long as its distance from the rayed dorsal fin,, the spine of 

 which terminates in a very long filament ; humeral process 

 rounded 8. S. filament osus, Blgr. 



b. Snout longer than the postocular part of the head ; 



spine of dorsal fin serrated in front ; 30 to 48 



movable mandibular teeth . 9. S. serratus, Hupp. 



B. Movable mandibular teeth more than half diameter of eye, 6 to 8 in number. 

 Maxillary barbel with a broad marginal membrane ; head more 



than once and one-third as long as broad ; humeral process 



rounded 10. S. sorex, Grthr. 



Maxillary barbel barbed or branched ; head not more than once 



and one-third as long as broad ; humeral process pointed . . 11. S. clarias, L. 



II. Gill-opening extending downwards beyond base of pectoral fin ; adipose dorsal fin touching 

 rayed dorsal fin. 

 Gill-openings widely separated ; mandibular barbels barbed but 



not margined ; 30 to 57 movable mandibular teeth .... 12. S. batensoda, Riipp 

 Gill-openings separated by a narrow isthmus ; mandibular barbels 

 barbed at the base, with a membranous margin at the end ; 

 6 to 9 very minute mandibular teeth 13. S. membranaceus^ Geoffr. 



The doubtful species Synodontis humeratus, C. & V., is referred to on p. 368. 



