Metoptoma. 
MOLLUSCA. 
105 
Obovate, its length and breadth being nearly equal, depres¬ 
sed ; vertex eccentric, situate about one-third of the length of 
the shell from the anterior end; external surface with about 
thirty obtuse, distant, rounded, divergent ribs, those upon the 
posterior end strongest. 
Lower Oolite, Stonefield. 
8. Patella Nanus _The Dwarf Patella, pi. XLVIII. fig. 
24, 25, 26. 
Patella Nanus . Sowerby, V. p. 134, pi. 484, fig. 3. Fle¬ 
ming, p. 288. 
Oblique, smooth, subconic; vertex obtuse, situate half way 
between the centre and the anterior end of the shell; both 
extremities equally obtuse; aperture oval. Fig. 26, the natural 
size of the shell. 
The London Clay, Ancliffe. 
9. Patella ancyloides. —The Ancilla-shaped Patella, pi. 
XLVIII. fig. 27, 28, 29. 
Patella ancyloides. Sowerby, V. p. 134, pi. 484, fig. 2. 
Convex, smooth, depressed; vertex slightly spiral, situate 
near the anterior end; the apex curved downwards, and a little 
to one side. Fig. 29, natural size of the shell. 
The London Clay at Ancliffe. 
10. Patella retrosa. — The Retroflexed Patella, pi. 
XLVIII. fig. 30. 
Patella retrosa. Phillips, II. p. 223, pi. 14, fig. 5. 
Subconic, smooth, depressed; apex retroflexed, acute, placed 
about two-thirds towards the anterior end; with about fourteen 
broad, flat, divergent, undulating ribs, and shallow, broad, inter¬ 
mediate furrows; aperture elliptical; margin undulated. 
Mountain Limestone, Bolland. 
11. Patella jequalis. —The Equal Patella, pi. XLVIII. 
fig. 31, 32. 
Patella mqualis. Sowerby, II. p. 87,* pi. 139, fig. 2. Fle¬ 
ming, p. 288. 
Abruptly conical, its height and breadth being nearly equal, 
smooth, with a few obsolete radii; posterior end nearly perpen¬ 
dicular; apex obtuse; base oviform, the anterior end broadest. 
In the Crag at Ilolywells. 
12. Patella curvata _The Curved Patella, pi. XLVIII. 
fig. 33. 
Patella curvata. Phillips, II. p. 223, pi. 14, fig. 4. 
Conical, smooth; anterior end curved; vertex inclined pos¬ 
teriorly, acute at the apex; aperture deep and orbicular; mar¬ 
ginal lip plane. 
The Mountain Limestone, Bolland. 
13. Patella latissima —The Very Broad Patella, pi. 
XLVIII. fig. 35. 
Patella latissima. Sowerby, II. p. 85, pi. 139, fig. 1 and 5. 
Fleming, p. 288. 
Depressed, smooth, and very thin; vertex eccentric, flat; 
concentrically undulated; aperture nearly orbicular, or slightly 
oval. 
In the Slaty Clay, Lincolnshire. 
14. Patella lateralis -The Lateral Patella, pi. 
XLVIII. fig. 36. 
Patella lateralis. Phillips, II. p. 223, pi. 14, fig. 6. 
Subconic, smooth; vertex depressed; the apex acute; pro¬ 
vided with a lateral sulcus, and posterior radiations. 
The Mountain Limestone, Bolland. 
Genus X—METOPTOMA_ Phillips . 
Shell subconical, depressed; vertex subcentral; face 
under the apex truncated; general form somewhat shield- 
shaped. 
1. Metoptoma imbricata —The Imbricated Metoptoma, 
pi. XLVIII. fig. 35 and 40. 
Metoptoma imbricata. Phillips, II. p. 224, pi. 14, fig. 8. 
Conical, shield-shaped; apex rather obtuse; surface covered 
with concentric, imbricated ribs. 
The Mountain Limestone at Bolland, and near Dowall, Der¬ 
byshire. 
2. Metoptona sulcata. —The Furrowed Metoptoma, pi. 
XLVIII. fig. 37. 
Metoptoma sulcata. Phillips, II. p. 224, pi. 14, fig. 11. 
Convex; posterior side arcuated; outer surface concentrically 
sulcated; apex obtuse. 
Mountain Limestone, Bolland. 
3. Metoptoma oblonga. —The Oblong Metoptoma, pi. 
XLVIII. fig. 38. 
Metoptoma oblonga. Phillips, II. p. 224, pi. 14, fig. 10. 
Oblong, cordiform; conical, rather convex; expanded ante¬ 
riorly, with the margin rounded; vertex obtuse. 
Mountain Limestone, Bolland. 
4. Metoptoma pileus. — The Bonnet Metoptoma, pi. 
XLVIII. fig. 39. 
Metoptoma pileus. Phillips, II. p. 224, pi. 14, fig. 7. Brown, 
Elts. Foss. Conch, p. 67, pi. 5, fig. 18. 
Shield-shaped, conical, smooth ; apex obtuse. 
Mountain Limestone, Bolland, and Dowall, Derbyshire. 
5. Metoptoma elliptica —The Elliptical Metoptoma, 
pi. XLVIII. fig. 41. 
Metoptoma elliptica. Phillips, II. p. 224, pi. 14, fig. 9« 
Elliptical, subconic, smooth; vertex terminal, acute, and 
elongated. 
Mountain Limestone, Bolland. 
