ACROLEPIS ORTHOLEPIS. 113 
3. ACROLEPIS ORTHOLEPIS, 7raguair. Plate X XV, figs. 7, 8. 
> ? oD ] 
ELONICHTHYS ORTHOLEPIS, Traquair. Geol. Mag. [3], vol. 1, 1884, p. 10. 
ACROLEPIS orTHOLEPIS, Traquair. Proc. Roy. Soc. Edinb., vol. xvii, 1870, 
p. 828; and Ann. Mag. Nat. Hist. [6], 
vol. vi, 1890, p. 492. 
— _ A. S. Woodward. Cat. Foss. Fishes Brit. Mus., pt. 1, 
1891, p. 508. 
Specific Characters.—Scales not serrated posteriorly ; those of the flank higher than 
broad ; tolerably coarse ridges and furrows run parallel with the superior, posterior, and 
inferior margins and meet at acute angles on a strong diagonal elevation which runs 
downwards and backwards over tle scale to the postero-inferior angle. 
Description—The type specimen, belonging to the British Museum Collection, is 
represented in Pl. XXV, fig. 7. ‘The length of this example is exactly twelve inches, 
but the tip of the snout is not present. It is also shghtly contorted or bent so that the 
back is more convex or gibbous than would otherwise be the case, while the ventral 
margin assumes a concave contour. Compression has also taken place in a somewhat 
oblique direction so that, the fish lying on its right side, the origin of the dorsal fin is 
slightly concealed by the scales of the left. 
The general contour of the fish is fusiform, with a powerful heterocercal tail. If we 
allow 3 inch for the missing part of the snout, the length of the head would be contained 
5% times in the total. 
The head has the usual Palzoniscid structure, but is so crushed and otherwise badly 
preserved that little more can be said of it. ‘Traces of fine striae are seen on the maxilla 
as well as on the mandible and on the opercular bones. ‘The supra-clavicular element of 
the shoulder girdle shows the same kind of ridged sculpture so general in species of this 
and allied genera. 
The scales are of moderate size and are not serrated along their posterior margins. 
Those of the flank (fig. 8) are higher than broad ; as stated above, the ornament of their 
exposed surfaces consists of tolerably coarse ridges and furrows which run parallel with 
the superior, posterior, and inferior margins and meet at acute angles a strong diagonal 
ridge or elevation which runs obliquely downwards and backwards over the scale to the 
postero-inferior angle. In the scales further back this diagonal ridge becomes less 
marked and finally disappears, and towards the tail pedicle the sculpture becomes 
reduced to interrupted furrows and punctures, arranged diagonally in the middle of the 
scale, but at the periphery tending to be parallel with the superior, posterior, and inferior 
margins. On the small narrow scales of the caudal body-prolongation these markings 
appear mostly as simple diagonal furrows. 
One of the pectoral fins is seen and attains a length of 14 inches, but it is not ina good 
state of preservation, its rays being rather broken up terminally and post-axially. I 
