On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 361 
“ Spine, slightly arched, much compressed, sides flat, anterior and posterior 
margins narrow, obtusely rounded ; section oblong, the long diameter being four to 
five times longer than the short ; teeth of the posterior margin slender, conical, pro- 
jecting at right angles to the spine ; teeth of the anterior margin large, thick, smooth, 
the upper sharp edge widest, closely adpressed to the surface ; surface closely 
covered with small irregular smooth granules, which under a strong lens are found 
to be radiatingly striated at their base, and with the intervening narrow spaces very 
minutely granulated. 
“When highly magnified the granulation of this spine resembles on a small scale 
the star-like style of ornament of the bony plates of Asterolepis (Eich). The base 
is imperfect, but apparently dilated in a remarkable degree, and in its present state 
the lower portion seems bent at a considerable angle from the curve of the rest of 
the spine” 
Formation and locality : Mountain Limestone, Armagh. 
Hz coll. Woodwardian Museum, Cambridge. 
Genus.—Homacanthus, Agass. 
Homacanthus—A gass, “ Poiss. Foss. Vieux Gres Rouge,” p. 113. 
% M‘Coy, ‘“ Brit. Paleoz. Foss.,” p. 632. 
‘‘Fin-spine, small, rather rapidly tapering, moderately arched backwards; sides 
flattened, converging to the anterior face, which is obtusely keeled ; sides covered 
with few very coarse, longitudinal ridges, and fine striz in same direction ; post- 
erior margin with two rows of denticles arched downwards ”—(M‘Coy). Base com- 
paratively large, with external cavity open posteriorly. 
Homacanthus microdus, M‘Coy. 
(Pl. XLVIIL., figs. 7-9.) 
Homacanthus microdus—F. M‘Coy, 1848. “Ann. & Mag. Nat. Hist.,” 2nd ser., Vol. II.,p.115. 
op f J. Morris, 1854. “Catal. Brit. Foss.” p. 329. 
9 " F. J. Pictet, 1854, “Traité de Paléont.,” Vol. II., p. 288. 
” » F. Moy, 1855. “Brit. Paleoz. Foss.,” p. 633, pl. 3 K, fig. 19. 
» % Morris & Roberts, 1862. ‘Quart. Journ. Geol. Soc.,” Vol. XVIIT., p. 101. 
” » Sie 1872. ‘Catal. West. Scot. Foss.,” p. 62. 
»” » J. J. Bigsby, 1878. “Thesaurus Devon.-Carb.,” p. 357. 
Spine, slender, arched posteriorly, length 2°0 inches, the base occupying one-fourth 
the entire length. Breadth at junction of base and exposed surface ‘2 of an inch, 
thence it gradually tapers toa fine point, base slightly attenuated. Transverse 
section triangular. Lateral surface with two or three longitudinal ridges, enameled 
and broad. Intermediate hollows wide and deep, flat at the bottom with, in some 
instances, a second series of minute longitudinal strie. Anterior margin formed by 
a broad enameled keel extending from the base to the apex. Dosterior surface 
3N2 
