CARBONIFEROUS FOSSILS OF IRELAND. 35 



EuoMPHALUs ANGUis. M'Coy. (PI. III. fig. 1 1). 



Sp. Ch. — Discoid; depresso-conical ; height of the spire equal to half the diameter, composed of five or six 

 rounded whorls, very gradually increasing, the last whorl very slightly exceeding the preceding one in diame- 

 ter; mouth round; umbilicus very wide, exposing all the whorls ; surface smooth, with fine, irregular lines of 

 growth, which bend forwai-d in passing over the circumference. 



The whorls of this species increase much less rapidly in size than in the E. rotundatus, or E. ucutus, the 

 last turn being very Httle larger than the preceding one, it is also much less elevated than either of those species ; 

 from the former, in particular, it differs in the small size of the basal whorls, and a slight flatness on their 

 upper part, which, at the same time that it makes them more nearly circular in the section, produces a very 

 obtuse keel, or convexity, on the upper part of the circumference, which is also marked by a sficrht retroflexion 

 of the linos of growth, as in Schizostoma, the striae of E. rotundatus are directly across. From the E. acutus it 

 differs in the small size of the last whorl, obsolete keel, and depressed form. Diameter one inch eight lines ; 

 height of spire ten lines ; height of mouth five lines. 



EuOMPHALUS BIFRONS. PMl. 

 Euomplialus bifrons. Phil. Geol. York. 



Sp. Ch. — Spire depressed, whorls very convex, obtusely carinated beneath, and bearing one spiral row of 

 large, nodular tubercles above. 



The spii-e of this species is composed of about five turns, very convex both above and below ; beneath they 

 are obscui-ely carinated, as in the E. pentangulatus, but above they are ornamented with a row of large, obtusely 

 roimded tubercles, about sixteen in a turn ; they are about their own diameter apart. Diameter one inch seven 

 lines, thickness six lines. 



EuOMPHALUS CALYX. Pllil. 



Euomphalus calyx. Phil. Geol. York. 



Sp. Ch. — Spire flat above; back very broad, flat; umbilicus deep, conical, margined by a sharp keel. 



This curious species has the back very broad and flat, so that, although the spire is not raised, the umbiH- 

 cus is very deep ; the flat, steep sides of the umbiHcus meet the back at an acute angle, so as to form a sharp 

 keel round the base of the shell; the upper surface resembles that of the E. catillus. Diameter one inch, thick- 

 ness five lines. It grows much larger. 



EuOMPHALUS CATULLUS. Mart. SP. 

 Helix catillus. Mart. Pet. Derb. — Euomphalus catillus. Sow. Min. Con. — Euomphalus catillus. Phil. Geol. York. 



Sp. Ch. — Spire concave, above ; whorls with a very sharp keel both above and below, near the outer edge, 

 back broad, but slightly convex. 



This species is much rarer than the E. i^entangulatus, from which it differs chiefly in having the keel on 

 the under side of the volutions, at least as sharp as that on the upper ; both keels are nearer to the outer ed^e 

 than in that species, and the back is consequently broader and flatter ; there are about the same number of 

 volutions in each. Diameter one inch three lines, thickness of last whorl six lines. 



