23 TELEOSTOMI. 



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



with fulcra Polyodoxtid^e, 20. 



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

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



ACIPEXSERID^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. 



Amiid-e, 23. 

 2777. Tail not evidently heterocercal (except in the very young). 

 Y. Scales cycloid. 

 A'. 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. . Exoccetid.e, 42. 

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

 tins inserted usually below axis of body; lower pharyngeals 

 separate. 

 M. Vent before ventrals; eyes rudimentary. . Amblyopsid.e, 36. 

 MM. Vent behind ventrals; e\-es normal. 

 X. Head more or less scaly. 



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

 posteriorly. 



P. Teeth cardiform, unequal Esocid^e, 39. 



PP. Teeth villiform, equal Umbeid.e. 38. 



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



laries alone Cypkinodontid^e, 37. 



7VW. Head without scales. 



Q. Gill membranes united with the isthmus; lower pharyngeals 

 falciform; mouth toothless; anterior vertebras coalesced. 

 JR. 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^e, 26. 



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



ten or more Catostomid.e, 25. 



QQ. Gill membranes free from the isthmus; lower pharyngeals 

 flatfish ; anterior vertebra? 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. 



Hiodontid.e, 27. 

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



Albulid.e, 28. 

 SS. Lateral line wanting. 



V. Mouth very wide, the maxillary reaching much beyond 



eye ; snout short. .... Stolephokidje, 31. 



VV. Mouth moderate, the maxillary scarcely extending 



beyond eye Clupeid.e, 30. 



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

 with the small mouth at the end Fistulariid.e, 44. 



