19 
and there are no intermuscular hones, hut all the arches seem to have been 
■well calcified, at least snperticially. The neural arches in the abdominal 
region appear comparatively small ; hut they are simnomited, as in Thrissops, 
by a correlated series of long, free, sigmoidally-hent rods, -which terminates 
immediately below the anterior part of the dorsal tin (PL Y, Pig, 2). The 
apparent arches may thus he in reality only the pedicles, while the rods above 
are neural spines ; on the other hand, the arrangement Avonld perha])s he 
interpreted by some as a series of dwarfed neural arches, Avith free “ inter- 
spinons hones ” above. In the caudal region the neural spines are distinctly 
fused with the pedicles. The large ribs are shoAvn, not quite reaching the 
inferior border of the abdominal region ; and the hyemal spines, as usual, are 
much enlarged at the base of the caudal fin. 
Appendicular Skeleton. — Pulcra arc conspicuous on the median tins, 
and are also seen on the pectoral tin of No, h. All the pectoral tin-rays, to 
the number of about tAvelve, and all the pelvic tin-rays, perhaps about six, are 
unjointed for a considerable length proximally ; Avhile the articulations of 
their divided and jointed distal portion are all distant. The dorsal fin is shown 
in the type specimen to comprise ten or eleven rays, Avhile the anal iii Nos. b 
and c exhibits at least fourteen rays. In Nos. candr;^ the opposition of these 
tAvo fins is clearly indicated, and the forked character of the caudal tin is also 
proved . 
Squamation.- -So far as can he ascertained, the scales differ in no 
respects from those of A. temm, the ridge-series having a similar aspect, and 
the other scales exhihiting only the concentric lines of groAvtli. Luiless, 
hoAvever, the small caudal region. No. e, is (h'ceptiAag there is evidence of a 
feAV rhomhic scales on the atrophied upper caudal lobe (PI. V, Fig. 4). 
Familtj — XEPTOLEPID^. 
Genus — LEPTOLEPIS, A yassiz. 
(Xcues Jiilirb. fur Mineralogie, ifcc., 1S32, p. 110.) 
Gen. Char . — Trunk elegantly fusiform. External head-hones and the 
opercular hones delicate, covered Avith smooth or feebly ornamented ganoine; 
snout obtusely pointed, and mandible prominent ; maxilla arched, Avith a 
convex dentigerous border, and dentary sharply rising into an obtuse coronoid 
process near its anterior extremity ; teeth minute, conical, and closely 
arranged ; prcoperculum broad mesially and marked Avith slight, radiating 
E 
