ACTJNOPTERYGII. 
Teeth small : operculum simple ; an 
enlarged scale at base of paired 
fins ; lateral line simple 
Teeth minute ; operculum subdivided 
bv transverse suture ; lateral 
line radiating on each scale tra- 
versed ; hindermost ray in dorsal 
and anal fins much elongated 
Teeth small ; operculum subdivided 
by transverse suture ; lateral line 
simple 
II. Parietal bones relatively small and not 
meeting in the middle line. 
Teeth small; no deep depression in 
frontal region of skull ; abdomen 
rounded or flattened 
Teeth small ; deep depression in 
frontal region of skull; abdomen 
compressed to sharp edge 
Teeth large and rounded; no deep 
depression in frontal region of 
skull 
Teeth large, laterally compressed ; no 
deep depression in frontal region 
of skull ; gape rather small . . . . 
Enlarged pair of teeth at symphysis 
of mandible ; gape wide ; dorsal 
fin opposed to pelvic pair 
As Spaniodon, but dorsal fin opposed 
to space between pelvic and anal 
fins 
III. Incertm Sedis, 
Elops (p. 22). 
Megalops (p. 24). 
Notelops (p. 27). 
Rliacolepis (p. 29). 
'Thrissopater (p. 32). 
Pachyrhizodus (p. 37) 
Esocelops (p. 46). 
Spaniodon (p. 48). 
Thrissopteroides (p. 
Teeth of moderate size and slender, 
each tipped only with a cap of 
enamel ; gape not much directed 
upwards 
Protelops (p. 56). 
Uenus ELOPOPSIS, Heckel. 
[Denkschr. k. Akad. Wiss., math.-naturw. Cl. vol. si. 1856, p. 251 .] 
,rw mn r.lT e ' Vhat latcrall y compressed, abdomen flattened. Man- 
lb e a httle prominent, and gape extending behind the eye; one 
supramaxillary bone ; margin of the jaws with a series of robust 
cornea cet . Operculum simple ; branehiostegal rays between 
■f and ' ° 111 ? umber - Vertebra between 50 and (iO in number, 
the centra not longer than deep, all slightly constricted and marked 
