81 
KEY TO FAMILIES OP PISCES. 
J. Jaws attenuate, forming a long, snipe-like beak. 
TT T ... Nkmiciithyid^, 56. 
JJ. Jaws not attenuate. 
filament Saccopiiaryxgid^, 54. 
KK. Tail not filamentous. 
M. Maxillaries and premaxillaries distinct.... Zoarcid^ 115 
MM. Maxillaries and premaxillaries more or less coaleLcent 
with vomer and palatines. 
GG. Body not eel-shaped. Axguillid.e, 53. 
N. Breast with a sucking disk. 
Lipahidid^, m 
AP? ; ? CYOLOPTEEIDA3 110. 
AN. Breast without sucking disk. 
P. Teeth in each jaw confluent into one. 
Q. Body compressed, rough.... ORTnAGomsciD/E, 131. 
QQ. Body not compressed, spinous. . Diodoxtid.e,’ 13o! 
PP. Teeth in each jaw confluent into two. 
T>TJT> rp Tetrodoxtid.e, 129. 
PPP. Teeth separate. 
R. Body enveloped in a bony box. . . Ostkaciid^, 127. 
RR. Body not mailed Strow 'I't 
CC. Gill membranes free from the isthmus. ’ ’ 
S. Yent at the throat. 
T. Vertical fins confluent ; body eel-shaped. 
Fierasferid^, 117. 
TT. Vertical fins separate; body oblong. 
.r, AmblyopsiDaE, 48. 
ob. Vent posterior. 
U. Caudal fin wanting ; body naked. 
TTTT , TKICHIURID.E, 73. 
LI U. Caudal fin present. 
V. Upper jaw prolonged into a sword. 
XiPiiiiD^^ 72. 
W. Upper jaw not prolonged into a sword. 
W. Body ovate, much compressed. 
STE03IATEID.E, 77. 
WW. Body oblong or elongate. 
X. Gill membranes broadly united; teeth 
present. 
Y. Dorsal fin of spines only. 
Bbexxiid^, 112. 
YY. Dorsal fin of soft rays only. 
COX^GROGAMD^E, 116. 
YYY. Dorsal fins 2, anterior spinous, 
posterior soft CoTXiDiE, 107. 
XX. Gill membranes seiiarate. 
Z. Jaws toothless, the lower jaw 
projecting — Ammodytid^, 69. 
ZZ. Jaws with teeth, lower not pro- 
jecting Ophidiid^, 118. 
Bull. Nat. Mus. No. 16- 6 
