4a Lips thick; P present; adults and large juveniles
with minute, embedded scales (not visible until
mucus is scraped off skin) ....... ANGUILLIDAE (No. 39)
4b Lips relatively thin (except Conger); P and scales
present or absent ....................... .................. ....... .. .. 5
5a Rear nostrils on midlateral part of snout just
before eye; P present; gill openings ventrolateral
and oblique, ventral and horizontal , or confluent
midventrally .......... SYNAPHOBRANCHIDAE (No. 46)
46 Co· . . · · · . . . ······ . . ······· ..... · . . · · . . · . .
5b Rear nostrils not close to eye; gill openings
lateral, wide or restricted (if gill openings are
ventral, then P & C are absent) ... .. ... .. ...... .. .. .. ....... .. ... 6
6a · One , median, frontal sensory pore between rear
edges of eyes; D & A end before C tip or, if C
present , rear nostrils a valve-like flap below
eye ... .. .. ....... .. .... .. ....... . .... OPHICHTHIDAE (No. 42)
42
6b No median frontal pore; D & A continuous with C .... .... . 7
7a P absent; rear nostril either near anterodorsal
edge of eye or medial to its posterodorsal
edge .... .. ... ... ............ .. NETTASTOMATIDAE (No. 47)
47
7b P present, sometimes reduced; rear nostril on snout
level with middle of eye or somewhat below ........ ....... ... S
ANGUILLIFORMES (EELS)
Sa Snout not much longer than eye
diameter .... ... .. ....... ... .. .. ......... . CONGRIDAE (No. 40)
Sb Snout length much greater than eye diameter
(except Derichthys) ............ ........................ . ............ 9
9a Vomerine teeth prominent , blade-like , in one row ..... ... 10
9b Vomerine teeth insignificant, in several rows ... ...... ..... . 11
lOa D origin over gill opening; P well
developed ..... ....... ....... MURAENESOCIDAE (No. 45)
lOb D origin behind anus; P a tiny inconspicuous
flap .......... .. ........ .. .. . ..... SERRIVOMERIDAE (No . 4S)
=e~
48
lla Snout and lower jaw blunt or only
moderately produced forwards ; premaxillaryethmoid teeth in.a broad, flat
plate .. ..... ... .. ............ ..... . DERICHTHYIDAE (No. 49)
- =
49
llb Snout and lower jaw elongated , beak-like ,
tips of beak typically curved apart; premaxillaryethmoid teeth in a long narrow patch on underside
of beak ............................... .. ...... ............ ........... . 12
12a Body short, truncated , arrow-like
CYEMIDAE (No . 50)
~ \= . . . . .
50
12b Body elongated , delicate, even
filamentous .. .. ...... ..... .. ... . NEMICHTHYIDAE (No. 51)
~" c~ ~~
-
0:::::::
159
with minute, embedded scales (not visible until
mucus is scraped off skin) ....... ANGUILLIDAE (No. 39)
4b Lips relatively thin (except Conger); P and scales
present or absent ....................... .................. ....... .. .. 5
5a Rear nostrils on midlateral part of snout just
before eye; P present; gill openings ventrolateral
and oblique, ventral and horizontal , or confluent
midventrally .......... SYNAPHOBRANCHIDAE (No. 46)
46 Co· . . · · · . . . ······ . . ······· ..... · . . · · . . · . .
5b Rear nostrils not close to eye; gill openings
lateral, wide or restricted (if gill openings are
ventral, then P & C are absent) ... .. ... .. ...... .. .. .. ....... .. ... 6
6a · One , median, frontal sensory pore between rear
edges of eyes; D & A end before C tip or, if C
present , rear nostrils a valve-like flap below
eye ... .. .. ....... .. .... .. ....... . .... OPHICHTHIDAE (No. 42)
42
6b No median frontal pore; D & A continuous with C .... .... . 7
7a P absent; rear nostril either near anterodorsal
edge of eye or medial to its posterodorsal
edge .... .. ... ... ............ .. NETTASTOMATIDAE (No. 47)
47
7b P present, sometimes reduced; rear nostril on snout
level with middle of eye or somewhat below ........ ....... ... S
ANGUILLIFORMES (EELS)
Sa Snout not much longer than eye
diameter .... ... .. ....... ... .. .. ......... . CONGRIDAE (No. 40)
Sb Snout length much greater than eye diameter
(except Derichthys) ............ ........................ . ............ 9
9a Vomerine teeth prominent , blade-like , in one row ..... ... 10
9b Vomerine teeth insignificant, in several rows ... ...... ..... . 11
lOa D origin over gill opening; P well
developed ..... ....... ....... MURAENESOCIDAE (No. 45)
lOb D origin behind anus; P a tiny inconspicuous
flap .......... .. ........ .. .. . ..... SERRIVOMERIDAE (No . 4S)
=e~
48
lla Snout and lower jaw blunt or only
moderately produced forwards ; premaxillaryethmoid teeth in.a broad, flat
plate .. ..... ... .. ............ ..... . DERICHTHYIDAE (No. 49)
- =
49
llb Snout and lower jaw elongated , beak-like ,
tips of beak typically curved apart; premaxillaryethmoid teeth in a long narrow patch on underside
of beak ............................... .. ...... ............ ........... . 12
12a Body short, truncated , arrow-like
CYEMIDAE (No . 50)
~ \= . . . . .
50
12b Body elongated , delicate, even
filamentous .. .. ...... ..... .. ... . NEMICHTHYIDAE (No. 51)
~" c~ ~~
-
0:::::::
159