1273 
Order Heteromi 
Body elongate* Jaw bones complete, little aberrant. 
Vomer obsolete. Palatines and pterygoides well developed. 
Cranium with condyle confined to basiocelpital. Exoccipital 
coalesced with epiotics and opisthotics. Opercular apparatus 
complete. Preopercle slightly connected with suspensorium. 
Suborbitals suppressed. Scapular arch formed by proscapula 
and posttemporal, latter detached from side of cranium and 
impinging on supraoccipital. Hypercoracoid and hypocoracoid 
coalescing in single lamellar imperforate plate. Actinosts 
normal. Anterior vertebrae separate. Air vessel with duct. 
Scales small. Ventrals abdominal, 
A.nalysls of families 
1 
a . Jaws normal; both jaws with teeth; dorsal spines 
separated, extend more or less length of back. 
Notacanthi dae* 
m mmi wnw» —"■» mm - ." ■ * — " m mtw m wa* — ate—» 
2 
a . Jaws form suctorial mouth; no teeth; dorsal 
•spines graduated, close together and form high 
angular fin little premedian. Llpogenyidae. 
