REPORT ON FOSSIL FISHES. 39 
the position and structure of the fins, the obtuseness of the posterior-inferior 
angles of the scales, and, last but not least, the possession of a peculiar scale 
ornament, consisting of ridges running parallel with the anterior, inferior, and 
posterior margins of the scale. These considerations indicate that Cycloptychius 
is the most appropriate genus to which to refer the present species, while, at 
the same time, the distinctions between it and Cycloptychius carbonarius are 
apparent at the first glance. In Cycloptychius carbonarius, the ridges on the 
scales are very much finer, that along the posterior margin being also more or 
less zigzagged in contour, while there is not that difference in the sculpture 
scales along the back which is so prominent a character in Cycloptychius con- 
centricus. The shape of the flank-scales also differs to a considerable extent ; 
for while in the former species the posterior-inferior angles are simply rounded 
off, in Cycloptychius concentricus they are absolutely obtuse, so that the inferior 
margin looks as much backwards as downwards. 
The genus Cycloptychius has not hitherto occurred below the horizon of 
the Millstone Grit. 
Position and Locality.x—Near Glencartholm, Eskdale, in the Cement-stone 
group of the Calciferous Sandstone series. 
Phanerosteon, gen. nov. Traquair. 
Shape fusiform; head typically paleoniscoid in structure; body for the 
most part destitute of scales, so that the internal skeleton is well exhibited. 
Fins well developed; anal commencing opposite the middle of the dorsal ; 
caudal heterocercal, only feebly bifurcated. 
Phanerosteon mirabile, sp. nov. Traquair. 
Pl. III. figs. 6-8. 
The entire length of the most perfect specimen is 2? inches, and in this 
measurement the length of the head is contained 4} times. The cranial roof 
bones are granulated with minute and occasionally confluent tubercles. The 
suspensorium is oblique, the operculum oblong, with rounded-off posterior- 
superior angle, and showing traces of fine ridges, corresponding with the lines 
of growth ; the interoperculum is somewhat quadrate-rhomboidal, with convex 
posterior margin. The maxilla, of the typical paleoniscoid shape, has its post- 
orbital portion marked with fine ridges, running parallel with the posterior and 
superior margins ; the dentary margin and infra-orbital process appear to be 
finely tuberculated. The slender mandible displays on its outer surface 
numerous delicate ridges obliquely inpinging on its upper margin; a few 
delicately striated branchiostegal plates are seen below it; no teeth can be 
NOL. XXX. PART @. G 
