On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain, 431 
that it was an inhabitant of salt water. The rounded form of the teeth, even 
where most worn only rendered smooth, and never hollowed out as in some 
other genera, may lead to the inference that the fish was wholly, or in part a 
vegetable feeder. 
Formation and locality : Mountain Limestone, Armagh. 
Ex coll. Eavl of Enniskillen 
Deltodus expansus, Davis. 
GPL, ILIDNL , ies, ©, TO, ails) 
Teeth, generally similar in arrangement to the type species, D. sublevis. Central 
pairs of teeth, of upper and lower jaws, are the only ones identified. In each pair 
they are widely expanded laterally, compared with D. sublevis. Teeth of the upper 
jaw are 1°1 inch in length, and ‘8 inch across the anterior margin; posteriorly they 
are constricted to an acute angle. Crown; asub-angular ridge extends from posterior 
angle to the anterior margin, dividing the surface into two unequal parts; the 
median portion slightly concave, with a marginal ridge extending along the edge 
to which the opposite tooth was attached—on the opposite side the surface is 
expanded, and forms a widely concave area with a lateral marginal ridge. The 
whole coronal surface is punctate. Anterior margin circular, the outer antero- 
lateral angle very slightly produced, lateral margins straight or very slightly 
convex, converging posteriorly to a somewhat acute and prominent apex, 
Teeth of the lower jaw wider than long, a broad ridge extends antero-posteriorly 
across the crown ; on the outer side of this ridge the surface is concave, depressed, 
and widely expanded, terminating in a raised lateral margin, surface pustulate ; 
transverse ridges absent. 
This species differs from D. sublevis in its more angular form, and its widely 
expanded concave surface. The posterior prominence is not so recurved and beak- 
like, and the anterior margin is more rounded; it lacks the acutely pointed 
antero-lateral angle, which is one of the characteristics of D. sublevis. 
Formation and locality : Mountain Limestone, Armagh. 
Hex. coll. Kaxl of Enniskillen. 
Deltodus aliformis, M‘Coy. 
(Pl. LIIL., fig. 12.) 
Peecilodus aliformis—F. M‘Coy, 1848, “Ann. Nat. Hist.,” Sec. Ser. Vol. IL, p. 129. 
” ” F. J. Pictet, 1854. <“Traité de Paléont.,” Vol. IL., p. 270. 
» » J. Morris, 1854. “Cat. Brit. Foss.,” p. 340. 
> » F. M‘Coy, 1855. “Brit. Paleeoz. Foss.,” p. 638, pl. 3 G., fig. 10. 
‘ 3 Morris and Roberts, 1862. ‘Quart. Journ. Geol. Soc.,” Vol. XVIII, p. 101. 
' " Young & Armstrong, 1871. “Trans. Geol. Soc., Glasgow,” Vol. IIT., Supt., p. 75. 
» » J. J. Bigsby, 1878. ‘Thesaurus Devon, Carb.,” p. 363. 
TRANS, ROY. DUB. SOC., N.S., VOL. I. 3 Y¥ 
