On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 531 
slightly imperfect along the inferior or shorter lateral margin is represented on 
Plate LXIV. ; figure 1a, represents the anterior face, and fig. 1, the posterior, the 
shortness of the latter in comparison with the former, and the convolutions of the 
rows of tubercles are well shown in this specimen. ‘Two sections are also given ; 
fi. 1c, represents a longitudinal section, and exhibits the thin, compressed antero- 
posterior form, whilst fig. 1b, serves to show its form a short distance from the 
basal extremity. It is possible that the two forms from Bristol and Armagh, may 
indicate sufficient differences to constitute separate species, but until further in- 
formation as to the general character of the whole fish be obtained, it may be better 
to regard them as modifications only of one species. The Bristol specimens are 
also in the Earl of Enniskillen’s Collection. 
The Museum of the Geological Society at Burlington House, contains two 
specimens of this genus of very large size. The locality from which they have been 
derived is not known. One of the specimens is preserved to the length of sixteen 
inches from the apex downwards, and the base, which is seven inches wide at the 
lowest part preserved, is broken and imperfect, and in all probability may have 
been several inches longer. The second specimen is also imperfect, it is represented 
on Plate LXIV., fig. 2, the part preserved is ten inches in length, and the base 
about seven inches wide, its width converges rapidly to about 3 inches, the remaining 
portion of the apical extremity is broken off. Both specimens are extremely flat 
and compressed, they are cracked and broken in several places, so that the flatness 
may be ina great measure owing to the instability of the extremely thin walls 
which are little more than the eighth of an inch in thickness. The bony substance 
of which they are composed is fibrous and has a strong tough appearance ; the 
surface is coarsely pitted in the spaces between the rows of tubercles, the latter 
are prominent, enamelled and smooth, and for the most part connected together so 
as to form long parallel ridges -25 of an incb apart. The under surface of the bone 
is smooth or striated longitudinally. The internal orifice is, of necessity, only 
about a quarter of an inch smaller than the external diameter. 
These specimens do not differ in any important particular, except in size, from 
those of Bristol or Armagh. 
Formation and locality : Mountain Limestone, Armagh. 
Ex, coll. Ear] of Enniskillen. 
Genus.—Stichacanthus, L. G. de Konincx. 
Stichacanthus—L. G. de Koninck, 1878, ‘Fauna du Calcaire Carb. de la Belgique,” p. 70. 
Professor de Koninck designates under this generic name species of tolerably large 
size, having the form of a recurved and depressed horn with a tolerably strong base. 
The surface is covered with a numerous series of longitudinal and parallel nodular 
ribs, The tubercles are prominent, somewhat elongated and attached the one to 
