28 TELEOSTOMI. 
J. Body naked; snout apes mouth wide, without barbels; caudal 
with fdlenan.s te Os . « POLYODONTIDA, 20. 
JJ. Body with 5 series at beny shields; head with bony shields; 
mouth inferior, toothless, preceded by 4 barbels; fins with fulcra, 
ACIPENSERID&, 21, 
TI. Caudal rounded or lanceolate; head with a bony casque. ; 
X. Scales ganoid (rhombic, enamelled _ no gular plate; fins with 
fulcra; dorsal finshort. . . . . . . LEPISOSTEIDs, 22, 
XX. Scales cycloid; a bony gular plate; no viideta: dorsal long. 
AmIIDs&, 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. . Exoca@rTip4, 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#, 36, 
MM, Vent behind ventrals; eyes normal. 
N. Head more or less scaly. 
O. Upper jaw not protractile, its margin formed by maxillaries 
posteriorly. : 
P. Teeth cardiform, unequal... . . . . Esocip#, 89, 
PP. Teeth villiform, equal. . . . - . UmBripa, 38 
OO. Upper jaw very protractile, its wage formed by premaxil- 
laries alone. . . . « . - »« CYPRINODONTIDS, 37. 
NN. Head without scales. 
Q. Gill membranes united with the isthmus; lower pharyngeals 
falciform; mouth toothless; anterior vertebra coalesced. 
R. Pharyngeal teeth larger, in one or more rows, the main 
tow with less than 8 teeth; dorsal (in native species) 
with less than 10 rays. . . . . . CYPRINIDA#, 26, 
RR. Pharyngeal teeth very numerous, in one row; dorsal rays 
tenormore. . . . . . . » CATOSTOMIDA, 25. 
QQ. Gill membranes free from the isthmus; lower pharyngeals 
flattish; anterior vertebra not modified. 
S. Lateral line present. 
T. Lower jaw with a gular plate; fins with scaly sheaths. 
ELorip#, 29, 
TT. Lower jaw without gular plate. 
U. Tongue with canine teeth; mouth terminal, oblique. 
HiopontTIp&, 27. 
UU. Tongue with blunt teeth; mouth inferior, horizontal. 
ALBULID&, 28, 
SS. Lateral line wanting. : 
V. Mouth very wide, the maxillary reaching much beyond 
eye; snout short. . + + « STOLEPHORIDA, 31. 
VV. Mouth moderate, the maxillary scarcely extending 
beyondeye . . 2... 2 we CLuPEIDs, 80. 
YY. Scales none; caudal with a ae filament; snout long, tubular, 
with the emall mouth attheend.. . . . FisTunarnps, 44. 
