366 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
‘‘ Posterior spine, three times as long as wide, breadth near its attachment main 
tained for about one-third its length, remaining two-thirds rapidly contracted, deeply 
curved, and ending in a fine point. Sides much compressed with a variable number, 
four to nine, of longitudinal ridges, which are smooth and less than their own diameter 
apart, the intervening spaces occasionally longitudinally striated ; along the anterior 
margin there is a well-defined carina; posterior concave surface with two regular 
close rows of small pointed denticles, directed obliquely downwards ; the surface 
towards the base is marked by small, scattered, oval, smooth tubercles, anterior 
branch more than twice the length, and about the same size at its origin, as the 
posterior one; a transverse section shows the height of the anterior branch to be 
double its width at the basal half, but it becomes depressed, so that its width is 
double the height in a section of the distal half; an internal cavity extends almost 
to the distal extremity, it is large compared with the diameter of the spine; it 18 
covered above and on the sides with close quincuncially arranged, smooth, oval 
tubercles ; near the extremity the spine becomes abruptly expanded and is covered 
with tubercles of much larger size, the extremity is generally curved downwards ; the 
basal partof the spine from which the two branches taketheir originis equal tothe wiath 
of their united bases, this is maintained for a short distance downward, after which 
the base becomes expanded to one and a half times its diameter above. The upper 
part is covered with smooth, rounded, shining tubercles, scattered indiscriminately ; 
lower, the base is much compressed and finely striated. with an abruptly truncated 
termination. 
The leneth of the base is 1-4 inch, its width at bottom 1-1 inch, near the top ‘7 
inch. The length of the posterior portion of the spine is 1°5 inches and that of the 
anterior 3:2 inches. 
Formation and locality: Mountain Limestone, Armagh. 
Ex coll. Earl of Enniskillen. 
Cladacanthus major, Davis. 
(Pl. XLVIL, figs. 6, 7.) 
Fragments of a second species of this peculiar genus of fish-remains occur at 
Armagh and may be consulted in the Enniskillen collection. They consist of portions 
of the longanterior part of the spineand include one example showing the extremity of 
this portion of the spine. By comparison with ( ). paradoaus, Ag., this one was about 
three lines larger. The anterior portion of the spine which js preserved is much 
compressed. Its lateral surfaces are covered with circular tubercles arranged in 
lines roughly parallel to the anterior margin. The tubercles are individually covered 
with minute dots or punctures only observable when highly magnified. The greatest 
breadth of the part of the spine preserved is *65 of an inch and at that point there 
