GasrERopopa. ] LOWER PALAEOZOIC MOLLUSCA. 299 
body whorl flattened, horizontal, bounded externally by a strong obtuse spiral keel; beneath which are two 
other keels less strongly marked, only one of which is visible on the spire, the lowest forming the cireum- 
ference of the body whorl; umbilicus small, scarcely shewing the inner whorls; base rounded; upper and 
under surface covered with equal, coarse, slightly undulating, irregular lamin of growth, forming thicker 
scales as they pass over the spiral keels. Diameter one inch ten lines, proportional diameter of last whorl <, 
depth of ditto =, diameter of umbilitus 3. 
The elevation of the spire, and the small size of the umbilicus, constantly distinguish this species from 
the Z. discors, as well as the difference of striation of the under side. 
Position and Locality—Not uncommon in the Wenlock limestone of Ledbury, Herefordshire, and near 
Ludlow, Shropshire ; common in the Wenlock limestone of Wenlock, Shropshire; Wenlock limestone of 
W oolhope. 
EUOMPHALUS SCULPTUS (Sow.) 
Ref—ld. Sow. Sil. Syst. t. 12. f. 17. 
Sp. Ch.—Discoid, very much depressed, of about three round, slightly elevated whorls; mouth nearly 
circular ; umbilicus very wide, exposing the volutions; surface covered with numerous smooth, very close, 
cord-like ridges, irregularly unequal in size (about seven in two lines on top of body whorl), separated by 
very narrow impressed sulci, scarcely one-fourth the width of the ridges. Diameter about one inch three 
lines, proportional diameter of last whorl =, diameter of umbilicus 3, height of last whorl %, height of 
spire about =. 
The absence of the transverse, scale-like sculpturing, and the very much more numerous and closer 
ridges, easily separate this from the 2. funatus. 
Position and Locality—Rare in the Wenlock limestone of Wenlock, Shropshire. 
EvoMPHALUS TRICINCTUS (A/*Coy). 
Ref—Sil. Foss. Irel. t. 1. f. 18. 
Sp. Ch.—Conical, apical angle about 95°; spire of about three rounded volutions, those of the spire 
having three very narrow, thread-like, spiral keels, one in the middle, one near the upper, and the third near the 
lower suture ; the body whorl has a fourth similar keel surrounding the umbilicus; all crossed by fine, sharp, 
oblique strize; base rounded, mouth nearly orbicular (slightly longer than wide); umbilicus deep, narrow. 
Diameter eight lines, proportional length of last whorl >, width of umbilicus 4, keels one and half lines apart. 
Position and Locality—tIn a conglomerate of angular fragments at Dol Fan, Rhayader, S. Wales; 
Bala sandstone of Dalquorhan, near Girvan, Ayrshire. 
EvoMPHALUS TRIPoRCATUS (M°Coy). Pl. 1. K. fig. 37 and 38. 
Sp. Ch.—Obtusely conic ; apical angle about 95°; spire of about three or four flattened whorls, each bearing 
three nearly equal and equidistant thick, obtuse carinee, one of which is at the suture, which it renders cana- 
liculate, one in the middle, and one forming the circumference of the basal whorl, and partly concealed by 
the suture in the spiral whorls; base convex, with three smaller spiral carinee, and a minute umbilicus; surface 
crossed by sharp, scaly, delicate, transverse strize. Width one inch, proportional length about 4, length of 
last whorl =. 
Col. Portlock has, I think, figured this species (Geol. Rep. t. 30. f. 3.) as the Z. subsulcatus of Hisinger, 
which has double the number of spiral keels on the upper surface. I should have referred those specimens to the 
E. cornu-arietis (His.), but that seems to have four large ridges to each whorl, and no indication is given in the 
figure or description of the spiral carinze on the base. It much resembles some of the varieties of the Plewroto- 
maria wmbilicata (Hall), from Bird’s-eye limestone of New York, but is certainly distinguished by its smaller 
umbilicus, and the three additional spiral keels on the base; those latter are generally best seen in the concavity 
left when the upper whorls of a specimen are broken away (described from internal casts). 
aQq2 
