482 On the Fossil Fishes of the Carbonifervus Limestone Series of Great Brutain. 
Homalodus trapeziformis, Davis. 
(Pi. LVIIL., fig. 30.) 
Teeth: trapeziform, large and strong, 1°12 inch in length, anterior margin 1‘1 
inch in breadth, greatest breadth across the posterior extremity 1:5 inch. 
Crown : flat, slightly bevelled towards the borders, depression in the left centre 
worn out by attrition. Coronal surface covered with enamel, minutely and 
irregularly punctate, the punctures towards the left lateral extension of the tooth 
gradually disappear and a reticulated arrangement of the enamel takes their place. 
Anterior extremity, convex ; the convexity extends without intermission along the 
left lateral margin forming a rude semicircle ; right lateral border, straight, the 
angle formed by it with the anterior margin is a right angle. Posterior border, 
slightly concave. Right postero-lateral angle slightly produced and acute. The 
left pcstero-lateral angle is much produced and extends °35 of an inch beyond the 
posterior margin, forming with the semicircular extension of the anterior margin 
an acute angle. Base not exposed. 
Formation and locality : Carboniferous Limestone, Armagh. Very rare. 
He. coll. Earl of Enniskillen. 
Homalodus quadratus, Davis. 
(EI, JENVIUOL, itp, Si.) 
Teeth : sub-quadrate in outline, length °8 of an inch, breadth in middle of tooth 
the same, diminishing slightly anteriorly and increasing about the same amount 
posteriorly. Crown, flat, with a very slight depression towards the left lateral 
border. Coronal surface thickly enamelled, uniformly punctate. Anterior margin, 
straight or very slightly concave. Lateral margin, straight, gradually diverging 
posteriorly. Antero-lateral angles, obtusely rounded. Posterior margin slightly 
convex. Left postero-lateral angle produced and acute. The enamel of the crown 
extends slightly beyond the marginal surface of the basal portion, and constitutes 
two-fifths of the whole thickness of the tooth. Posteriorly the tooth is -25 inch in 
thickness ; anteriorly this is diminished to ‘17 of an inch. Root, smaller than 
crown but conforms generally to it in form. Transverse section, slightly convex 
in centre, concave towards each lateral margin. Longitudinal section straight. 
Surface, smooth, longitudinally striated. 
This species may be distinguished from Homalodus trapeziformis by its square 
form and the much dimininshed size of the left postero-lateral angle. The large 
development of the left lateral extension of H. trapeziformis giving the whole of 
the anterior and lateral margins a semicircular form, does not occur to nearly so 
large an extent in H, quadratus, though it has similar distinctive features developed 
in a minor degree. 
Formation and locality : Carboniferous Limestone, Armagh, Very rare, 
He coll. Earl of Enniskillen. 
