50 
ACTINOPTERVGII. 
Synopsis of Genera. 
I. Trunk regularly and deeply fusiform. 
(a) Teetli all styliform, or reduced within 
the mouth. 
Dorsal fin arising well in advance of 
anal; no enlarged ridge-scales . . 
Dorsal fin arising well in advance of 
anal; dorsal ridge-scales prominent 
Dorsal fin arising well in advance of 
anal; scales comparatively thin, 
and much the thinnest on caudal 
region ; no enlarged ridge-scales. . 
[Genus known only by detached scales, 
which are much deeper than 
broad, with a narrow overlapped 
margin, a large* peg-and-socket 
articulation, and no sharp inner 
keel; hinder border denticulated. 
Dorsal fin opposed to anal; dorsal and 
ventral ridge-scales prominent . . 
( b ) Marginal teeth styliform; inner teeth 
stouter and mostly tritoral. 
[Genus known only by marginal teeth, 
of which crown is expanded to 
chisel- or gouge-shaped edge .... 
Dorsal fin arising well in advance of 
the anal, both these fins much 
elevated and fringed with fulcra 
which are scarcely enlarged at 
the base; angles of overlapped 
margin of scales not produced . . 
Dorsal fin arising well in advance of 
the anal, neither of these fins 
excessively elevated, but with a 
cluster of enlarged fulcra at the 
base; angles of overlapped mar¬ 
gin of scales produced forwards; 
no gular plate. 
II. Trunk much deepened, often irregular in 
form. 
Trunk very deeply fusiform or regu¬ 
larly cycloidal; teeth stout and 
styliform, clustered within the 
mouth; dorsal fin much extended 
and anal opposed to its hinder 
half; all scales rhombic, with 
feeble inner rib; ridge-scales in¬ 
conspicuous ... 
Acentrophorus (p. 51). 
Semionotus (p. 55). 
Aphnelepis (p. 64). 
Serrolepis (p. 65).] 
Pristisomus (p. 66). 
Sargodon (p. 67).] 
Colobodus (p. 68). 
Lepidotus (p. 77). 
t 
Dapedius (p. 128). 
