SEMIOXOTIDJE. 
81 
the neural arches in the abdominal region are separate and not 
anchylosed with the neural spine; the ribs are long and slender, 
apparently extending to the ventral border. 
In the pectoral arch the clavicle is relatively much expanded, 
though pointed, below; and it tapers irregularly above where over¬ 
lapped by the supraclavicle. Immediately behind the longitudinal 
bend in the element the outer surface is covered with a rugose 
thickening, marked with vermiculating rows of denticles of ganoine. 
The supraclavicle is narrow, about half as long as the clavicle, 
and firmly articulated at its thickened upper end with the small, 
almost club-shaped post-temporal. The basal bones of the pectoral 
fin are large and much elongated, slightly expanded at each end, 
and more than five in number. The pelvic fin-supports are unknown. 
Biserial fulcra are present on the anterior border both of the paired 
and median fins; and the supports of the dorsal and anal are much 
enlarged beneath them. 
The supratemporal plates vary much in arrangement in different 
species of Lepidotus , but they always overlap both the cranial roof- 
bones and the most anterior dorsal scales. In L. latifrons there is 
one not quite symmetrical pair of outer plates, occupying the space 
between the operculum, squamosal, and parietal on each side; and 
there are three symmetrically arranged plates, no larger than 
ordinary scales, apposed to the hinder margin of the parietals. In 
L. mantdli the supratemporals are in three pairs, the two outer 
ones corresponding to the single outer pair in L. latifrons. In 
L. elvensis , as already described by Quens-tedt, the supratemporal 
series consists of a single pair of large plates, as in Amia. 
There is a series of postclavicular scales, but only two on each 
side are much enlarged. These two scales extend the whole depth 
of the flank, the uppermost being longest and narrowest. There 
are also three enlarged scales round the anus, which seems to have 
been mesially placed; their exposed portion is cycloidal, and the 
hinder margin usually serrated. Nearly all the other scales are in 
regular series, and those of the flank are united by a feeble peg- 
and-socket articulation; a single row of scales, however, at the base 
of the dorsal, anal, and caudal fins does not conform to the regular 
flank-series, but is directly related to the fin-rays and fulcra. All 
the flank-scales are deeply overlapping, and most of them exhibit 
a forward production both of the antero-superior and antero-inferior 
angle; in some of those of the foremost series the overlapped 
portion is wider than the exposed area. The dorsal and ventral 
ridge-scales are never much enlarged; they are inconspicuous in 
the more robust species, but appear as a serrated ridge on the back 
in those which are more laterally compressed. 
PART III. Gr 
