232 
DESCRIPTION OF THE FOSSILS. 
X. goniolobus. Ph. PL XVII. fig. 23. Bolland. 
Subglobose, involute, umbilicus small ; sutures retroflexed into a round dorsal 
sinus ; first lateral lobe angular ; second inconspicuous. 
N. globatus. Sow. PI. XVII. fig. 20, 28 ? Bolland. 
The umbilicus appears less angular than in Min. Conch. 
N. bistrialis. Ph. PI. XVII. fig. 21. Bolland. 
Two or three spiral striae on the edge of the large umbilicus. 
N. bilobatus. Sow. t. 249- Closeburn ; Coalbrookdale. 
Subglobose, transversely striated, umbilicus very deep ; septa with one deep forward 
bend on the back ; siphunculus central. 
N. cyclostomus. Ph. PI. XXII. fig. 26 ; PI. XVII. fig. 29 ; PL XVIII. 
fig. 3. Castleton ; Bolland ; High-Green-wood. 
Shell partly spiral, rapidly enlarging to a nearly straight cone ; crossed by fine 
flexuous striae ; sutures concave outwardly, slightly retroflexed on the back. Aperture 
nearly round. Siphunculus near the outer edge. Number of spirals variable. 
N. tuberculatus. Sow. PI. XXII. fig. 27, 29- High-Green-wood ; 
Kildare. 
Discoidal, calyciform, striae retroflexed on the broad back ; edges of the umbilicus 
tuberculated : septa concave outwardly ; siphuncle central. In young shells two lateral 
ridges appear. 
X. multicarinatus. Sow. Cork ; Cumberland. 
Cylindrico-discoidal ; back flattened, with many spiral ridges and furrows. 
N. cariniferus. Sow. Pl. XVII. fig. 19- Kildare; Coalbrookdale; 
Cork ; Bolland. 
Globoso-discoidal, inner whorls half exposed in a large conical umbilicus, bounded 
by a sharp ridge ; two spiral ridges and retroflexed stria? on the back. Septa concave 
outwardly, siphuncle nearer the outer edge. 
N. ingens. Mart. Pl. X VIII. fig. 4. Coniston near Gargrave ; Clat- 
tering dykes. 
Discoid, inner turns a little concealed, back round, aperture orbicular, obscurely 
angular toward the inner edges, septa numerous, siphuncle central. Its round back is 
the only difference from N. pentagonus of Sowerby. 
N. biangulatus. Sow. Pl. XVII. fig. 22. Ireland ; Bolland. 
Spheroidal with a large deep umbilicus ; a keel upon each side in young specimens ; 
aperture transversely elliptical ; siphuncle central ; septa very concave. 
N. sulciferus. Ph. Florence Court ; Enniskillen. 
Spheroidal, umbilicus large, deep, bordered by a raised angle or keel, back 
bevelled toward the keels, and sulcated in the middle. Closely allied to the pre- 
ceding species. 
