SILUEID.E. 219 



B. Dorsal fin divided into two, the posterior portion adii)Ose. 



Sides of head protected by bony shields ; adi- 

 pose dorsal fin large and supported by 

 bony rays (the produced neural spines) . 6. Heterohranclius, Geoff r., p. 272. 



Sides of head naked, only the postorbital shield 



being present ; adipose dorsal fin small . 7. Biaotopterus, Blgr., p. 276. 



II. Plotosin^. — A sliort dorsal fin in front, with a pungent spine ; a second 



dorsal and a long anal, united with the caudal; gill-membranes free from 

 isthmus; air-bladder moderately large, free. 



8. Flotosus, Lacep., p. 278. 



III. SiLURiN.^. — Dorsal fin very short or absent ; adipose dorsal fin very small ; 

 anal fin much elongate ; gill-membranes free from isthmus. 



A. Dorsal fin with a spine. 



Adipose fin present 9. Eatropius, M. & T., p. 270. 



Adipose fin absent 10. Schilhe, Cuv., p. 203. 



B. T3orsal fin without spine; adipose fin present. 



Teeth absent 11. Sihwanodon, Blkr., p. 208. 



C. No rayed dorsal fin. 



Adipose fin present 12. PhysaUia, Blgr., ^. 300. 



Adipose fin absent 13. FaraiUa, Blgr., p. 302. 



IV. Bagrin^. — Dorsal fin short; adipose fin present, or transformed into a 

 second rayed fin ; anal fin short ; gill-membranes free or very narrowly 

 attached to isthmus. 



A. Gill-membranes more or less notched in the middle ; nostrils widely 

 separated from each other. 



1. Nasal barbel present*. 

 a. Teeth on the palate. 



Dorsal fin v^^ith 8-11 branched rays; adij)ose 



fin very large 14. Bagrus, ('uv., p. 304. 



Dorsal fin with b-^ branched rays ; adipose 



fin moderate or small 15. Chri/sichth(/K, Blkr., p. 314:. 



Dorsal fin with branched rays ; second dorsal 



fin rayed, with an anterior spine in the 



adult It). Ckiroteif, Kner, p. 341. 



h. Palate toothless. 

 Dorsal with 6-7 branched rays 17. GeplujroijJan'is, Blgr., p. 344. 



2. Nasal barbel absent. 



a. Anterior nostril on uj)per surface of snout; dorsal with 5-7 branched 

 rays. 



Sometimes very niinute iu Gcph>jvo<jhitils. 



