PLATE XCI. 
2> ^ Corbula Galliea. ( Maple-like Corbula.) Transversely ovate; larger valve turgid; umbones, with transverse striae; beaks smooth: 
smaller valve, with longitudinal rays. * 
I. C. Curtansata. (Shortened Corbula.) Transverse; anterior side large, rounded; beaks central; surface smooth, with well-marked lines 
of growth ; basal line triangular. 
•). C. Depressa. (Depressed Corbula.) Sub-orbicular; beaks central, produced; anteriorly finely rounded; basal line arcuated; surface, 
with concentric ndges;and a few lines of growth. * 
*>♦ 7. C. Longipostpum. (Long-beaked Corbula.) Transversely ovate ; with thin, concentric striae; beak long in front; umbones minute. 
„ . y ’ (Little Shield Corbula.) Transversely ovate, thick, globose; beaks short in front; umbones large, recurved, prominent; 
surface, with sealariform stria?. or. 
10. C. Hennahii. (Hennah's Corbula.) Transversely elongated, ovate; short beak posteriorly; convex; valves unequal; posterior side 
truncated; surface smooth. 
II. Venus Elliptica. (Elliptical Venus.) V. Plate LXXXIIL, Fig. 9. 
1-2- C. Fieus. (Fig Corbula.) Orbicular ; with posterior side projecting into beak ; surface, with strong, transverse stria?; beaks obtuse. 
i cl Cuspidata. (Pointed Corbula.) Tumid, transversely oblong, sub-equilateral; anterior side pointed, carinated; lower margin of 
left valve expanded, inflated; disc rugged. Length, £ in.; breadth, f in. 
lo. C. StPlata. (Striated Corbula.) Transversely oval; beak short; surface, with many, fine, transverse strife. 
16, 17, 18. C. Revoluta. (Revolved Corbula.) Tumid, transversely oblong; anterior side produced, truncated, with keel to beak; margin of 
lower valve prominent, inflected ; beaks unequal; transversely sulcated ; larger valve, enveloping edge of smaller, and revolving inwards. 
19. C. Globosa. (Globular Corbula.) Globular, smooth; anterior side of larger valve produced into a lip, obtuse in front; posterior side 
round; beaks equal. 
20. C. Pisum. (Pea-shaped Corbula.) Sub-globular; anterior side truncated; margin of one valve produced; beaks unequal; surface, with 
concentric sulci. 
• * C. Striatula. (Minutely-Striated Corbula.) Ovate, ventricose; valves equal; minutely striated; beak long, straight, doubly channelled 
internally. 
23, 24. C. Elegans. (Elegant Corbula.) Sub-globular; with concentric sulci; posterior side produced, smooth, truncated; left valve sub- 
triangular, smooth}; beak of sulcated valve curved. 
C. ObSCUPa. (Obscure Corbula.) Gibbose, ovate, smooth; posterior side flattened. 
20, 27, 28. C. Costata. (Ribbed Corbula.) Transversely oblong, tumid; anterior side narrowed, produced, pointed, truncated; surface, with 
a few, transverse sulci. 
29. C. Nitida. (Shiningfiorbula.) Gibbose, ovate, sub-trigonal, equilateral; anterior side truncated, smooth, shining; valves equal; beak 
produced, inflated. 
30. C. Complanata. ( Flattened Corbula.) Depressed, transversely ovate, elongated; anterior side small, sub-truncated, defined by obtuse 
ridge ; posterior portion of right valve depressed, thickened ; surface, with seven or eight, transverse sulci; left valve convex, enveloping the right. 
31. C. Rotundata, (Rounded Corbula.) Gibbose, ovate, sides equal; posterior side truncated; beaks produced; with concentric sulci. 
32,33. C. Tpuncata. (Truncated Corbula.) Transversely oblong-ovate; beaks large, central; posterior side produced, truncated, pointed; 
surface, with transverse stria?. 
34. C. Alata. (Winged Corbula.) Sub-orbicular, convex; anteriorly rounded; posteriorly contracted, truncated; surface smooth; beaks 
incurved. 
35. 
36. C. Punctum. (Punctured Corbula.) Triangular, convex, oblique ; beaks produced; sides straight; surface, with longitudinal and trans¬ 
verse stria?, apparently punctures. 
37. Amphidesma Securiforme. (Hatchet-shaped Amphidesma.) Transversely oblong-ovate ; beaks obtuse, central, narrowed and rounded 
at both ends; surface smooth, with remote lines of growth. 
37*. Maetra Angnlata. (Angulated Mactra.) Triangular, convex ; posterior side, defined by a ridge ; beaks small, central, approximating; 
surface smooth. 
38. C. Gigantea. (Gigantic Corbula.) Gibbose, transversely oblong; anterior side produced, recurved; posterior side, with short spines; 
surface, concentrically sulcated near beaks. 
39. A. Deltoid©. (Deltoidal Amphidesma.) Orbicular, inflated; anteriorly rounded ; posteriorly truncated ; with well-defined, diagonal ridge 
from beak to margin. 
40. A. Portlockii. (Pordock's Amphidesma.) Sub-orbicular; posteriorly truncated, with inflection of margin below truncation ; beaks central, 
obtuse; surface, apparently once with concentric strife. 
41. A. Axiniforme. (Axe-shaped Amphidesma.) Triangular; beaks central; posteriorly truncated ; surface smooth. 
42. M. Striata. (Striated Mactra.) Sub-trangular, convex; sides equal; beaks central; lateral teeth prominent; surface, with strong, con¬ 
centric stria?. 
43. M. Subtruncata. (Sub-trimcatcd Mactra.) Sub-triangular, inequilateral, strong, convex; posteriorly acuminated, flattened; surface, 
with transverse stria\ 
44,45. A. Carbonariura. ( Oval Amphidesma.) Orbicular, convex; anteriorly rounded; posteriorly truncated, squarish; beaks prominent, 
inflected, remote. 
46. A. Album. (White Amphidesma.) Transversely ovate, sub-triangular, rounded at both ends; beaks sub-central; surface smooth. 
47. A. Prismatieum. ( Prismatic Amphidesma.) Transversely oblong-ovate, compressed, thin, fragile; posteriorly acuminated, with slight 
sub-truncation; surface, with minute, concentric stria?. 
48. A. Tenuistriatum. (Thin-striated Amphidesma.) Transversely elongated, sub-ovate, flat; posteriorly sub-truncated; beaks central, 
obtuse ; surface, with many, concentric stria?. 
49. A. Reeurvum. (Recurved Amphidesma.) Transversely oblong-oval; beaks large, produced, sub-central; surface smooth, with shallow 
lines of growth. 
50. M. Glauea. (Grey Mactra.) Sub-triangular, convex, thin; beaks central, obtuse, inflected; anteriorly wrinkled ; surface, with concentric 
strife. 
51. M. Depressa. (Repressed Mactra.) Thin, trigonal, depressed; umbone 3 prominent; cardinal teeth simple; lunnle depressed, plain. 
52. M. Deaurata. (Gilded Mactra.) Oblong-oval, inequilateral, flat; beaks obtuse, incurved; posteriorly sub-truncated; surface smooth. 
53. 57, 58. M. Solida. (Strong Mactra.) Sub-triangular, strong; sides equal; surface smooth, with a few, concentric wrinkles. 
54. M. Stultorum. (Foolish Mactra.) Sub-triangular, thin, convex; beaks central, prominent, inflected; sides equal; surface, with flue, 
concentric strife. 
55. M. Truncata. (Truncated Mactra.) Triangular, convex, strong, thick ; sides equal, straight; surface smooth, with a few lines of growth. 
56. M. Areuata. (Arcuated Mactra.) Ovate,' sides arched ; hinge narrow ; lateral teeth striated; surface smooth, with a few lines of growth. 
( no ) 
