ACTINOPTERTGII. 
temporal bone scales cycloid, 
regularly arranged ateral line 
above middle of flank. 
Premaxilla completely excluding 
maxilla from margin of upper 
jaw; opercular apparatus com¬ 
plete ; scapular arch supported 
by post-temporal bone; body 
with paired longitudinal series 
of scutes; lateral line piercing 
a series of scutes above middle 
of flank. 
(d) Supraoccipital separating the parietal 
bones in the middle line; squa¬ 
mosal bones much reduced, and 
pterotic region prominent. 
Maxilla partly entering gape; upper 
dentition chiefly on inner bones 
of mouth ; abdominal vertebrae 
without transverse processes; 
an adipose dorsal fin; scales 
minute or absent, but usually 
rows of scutes, the dorsal series, 
when present, being unpaired. . 
Premaxilla completely excluding 
maxilla from margin of upper 
jaw; dentition usually feeble, 
but upper enlarged teeth, when 
present, on the premaxilla; ab¬ 
dominal vertebrae without trans¬ 
verse processes ; an adipose 
dorsal fin scales usually pre¬ 
sent, no scutes. 
Premaxilla delicate but completely 
excluding relatively large max¬ 
illa from margin of upper jaw ; 
dentition absent or on ianer 
bones; abdominal vertebrae with 
transverse processes; no adipose 
dorsal fin ; dense regular squa- 
mation. 
Premaxilla completely excluding 
maxilla from margin of upper 
jaw ; dentition feeble or absent; 
abdominal vertebrae with trans¬ 
verse processes; paired fins ex¬ 
cessively enlarged . 
Premaxilla small, and maxilla form- 
Notacanthid^ (p. 168). 
Dercetid^ (p. 171). 
Enchodontid.® (p. 189), 
ScOPELID^ (p. 235). 
Gonorhynchid.® 
[(p. 271). 
Chirothricid^ (p. 279). 
