110 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 
reference of which to the genus Acrolepis is sufficiently obvious, and I am also unable to 
see any specific difference between them and those appertaining to other remains of the 
genus from Yorkshire, Lanarkshire, etc. 
A series of thirteen fragments apparently belonging to one fish, from the Millstone 
Grit of Hebden Bridge, Yorkshire, and in the Davis Collection, British Museum, repre- 
sents to my mind a species identifiable with that of M‘Coy’s scales from Derbyshire. 
One of these fragments, which shows an extensive portion of the squamation of the right 
flank, is represented in Pl. XXIV of the natural size. It must have belonged to an indi- 
vidual of between two and three feet in length, yet the scales do not seem proportionally 
very large. ‘I'he exposed portion of the scales on the middle of the flank is about ¢ in. 
in breadth, and perhaps a little more in height, and is covered with well-marked ridges, 
sub-parallel, closely placed, occasionally branching and intercalated, their main direction 
being obliquely downwards and backwards across the surface of the scale, the posterior 
border of which is not denticulated. On an average fifteen of these ridges may be 
counted in the height of one of these flank-scales. 
Another fragment shows some remains of the head, of which the most interesting is 
the parietal part of the cranial roof. ‘This is ornamented with closely set, wavy, 
undulating rounded striz, mostly longitudinal in their direction, and often looped, 
branching and interrupted, and at some places passing into tubercles. A similar orna- 
ment apparently characterised also the opercular bones, though it is not extensively seen. 
A portion of the clavicle is also seen, with strong striae running in a transverse direction, 
On the mandible the striz are longitudinal in their direction, but they are also extensively 
broken up into long-shaped tubercles. The maxilla is also seen, its post-orbital expan- 
sion being very strong, but as the outer surface is not seen its sculpture cannot be 
described. 
Pl. XXIII represents an Acrolepis from the “ Low Main” Coal Shale at Newsham, 
Northumberland, and contained in the Atthey Collection in the Newcastle Museum, 
which I have no hesitation in referring to the same species as the above. As it lies the 
specimen measures 13} inches in length, but being obliquely cut off just behind the 
ventral fin, its original length can scarcely have been less than 2 feet. ‘The scales are 
much jumbled and confused, but agree in sculpture with those already described. The 
head is very well preserved ; the antero-superior border of the left orbit is shown as well 
as the nasal opening of that side. ‘he cranial roof-bones are, like those of the Hebden 
Bridge specimen, mainly striated, the ridges tending in places, especially on the snout, 
to pass into tubercles. ‘The mandible is also longitudinally striated, and the broad post- 
orbital part seems also to have possessed a similar ornament, though its infra-orbital 
process is tuberculated. The pectoral fin is pretty well shown, though its distal 
extremity is somewhat frayed. From the figure it will clearly be seen that the principal 
rays are unarticulated for at least the first third of their length, and that the anterior 
margin is furnished with closely set prominent fulcra. The ventral fin is situated 6 
