28 TELEOSTOMI. 



J. Body naked; snout epatulate; mouth wide, without barbels ; caudal 

 with fulcra ...... . ..... POLYODONTID^E, 20. 



JJ. Body with 5 series of bony shields; head with bony shields; 

 mouth inferior, toothless, preceded by 4 barbels; fins with fulcra. 



ACIPENSERID.E, 21. 



II. Caudal rounded or lanceolate ; head with a bony casque. 

 X. Scales ganoid (rhombic, enamelled plates); no gular plate; fins with 

 fulcra; dorsal fin short ........ LEPISOSTEID^E, 22. 



XX. Scales cycloid ; a bony gular plate ; no fulcra ; dorsal long. 



AMIIDJE, 23. 



HH. Tail not evidently heterocercal (except in the very young). 

 Y. Scales cycloid. 



K. Side of belly with a conspicuous ridge or lateral line ; pectoral fins 



inserted high, on or above the axis of the body ; lower lobe of 



caudal longest; lower pharyngeals united. . EXOCCETIDJE, 42. 



KK. Edge of belly without conspicuous ridge or lateral line; pectoral 



fins inserted usually below axis of body ; lower pharyngeals 



separate. 



M. Vent before ventrals ; eyes rudimentary. . AMBLYOPSID.E, 36. 

 MM. Vent behind ventrals ; eyes normal. 

 N. Head more or less scaly. 



0. Upper jaw not protractile, its margin formed by maxillaries 



posteriorly. 

 P. Teeth cardiform, unequal ....... ESOCID^E, 3J. 



PP. Teeth villiform, equal ....... UMBRID.E. 38. 



00. Upper jaw very protractile, its edge formed by premaxil- 

 laries alone ........ CYPRINODONTIDJS, 37. 



NN. Head without scales. 



Q. Gill membranes united with the isthmus; lower pharyngeals 



falciform ; mouth toothless ; anterior vertebrae coalesced. 

 H. Pharyngeal teeth larger, in one or more rows, the main 

 row with less than 8 teeth; dorsal (in native species) 

 with less than 10 rays ...... CYPRINID^;, 20. 



RR. Pharyngeal teeth very numerous, in one row; dorsal rays 

 ten or more ........ CATOSTOMIDJE, 25. 



QQ. Gill membranes free from the isthmus; lower pharyngeals 



flattish ; anterior vertebras not modified. 

 S. Lateral line present. 



T. Lower jaw with a gular plate ; fins with scaly sheaths. 



ELOPID.E, 29. 

 TT. Lower jaw without gular plate. 



U. Tongue with canine teeth ; mouth terminal, oblique. 



HlODONTID^E, 27. 



UU. Tongue with blunt teeth ; mouth inferior, horizontal. 



SS. Lateral line wanting. 



V. Mouth very wide, the maxillary reaching much beyond 

 eye ; snout short ...... STOLEPHORIDJS, 31. 



VV. Mouth moderate, the maxillary scarcely extending 

 beyond eye ........ CLUPEID^S, 30. 



YY- Scales none; caudal with a long filament; snout long, tubular, 

 with the small mouth at the end. . . FISTULARIID^. 44. 



