PLATE XC. 
I, 2, 3. Petricola Inflata. (Inflated Petricola.) Sub-triangular, gibbose, cordiform ; beaks produced, approximate ; posterior side obliquely 
truncated; surface smooth, with an obscure ridge on posterior side from beaks to margin, and shallow lines of growth. 
• i ^^ m i nosa * ( Ram \nated Petricola.) Ovate, gibbose, anterior side short, rounded; beaks obtuse, approximate; with one, cleft tooth 
m valve and two, small ones in the other; surface, with laminated, concentric ribs. Fig. 5 a variety. 
... 6 .* 7 ‘ (Smooth Petricola.) Obovate, sub-compressed; beaks produced, approximate; anterior side short, rounded; surface smooth, 
with irregular lines of growth. 
•*T. 8 ^^ angUin0laria Lirata * ( md 9 ed Sanguinolaria.) Transversely elongated, convex; posteriorly sub-truncated, ridged; surface smooth 
with filiform strife, parallel to margin. 
9. s. HoUowayii. (Holloway's Sanguinolaria.) Transversely elongated; beaks minute ; posterior side short; surface smooth, with shortish 
lines of growth ; with sulcus from beak on anterior side to margin ; shell thin. 
10, 21. Potomomya Gregaria. ( Gregarious Potomomya.) Sub-triangular; anterior side of right valve produced, truncated ; posterior side 
with remote tooth and slight sulcus within anterior edge; beaks depressed, obtuse ; surface smooth. 
II. S. Attenuata. {Attenuated Sanguinolaria.) Transversely elongated; attenuated posteriorly; rounded at ends; surface smooth: without 
diagonal ridge. 
12. S. Angnstata. {Narrowed Sanguinolaria.) Transversely elongated, compressed; posterior side Bmooth, with diagonal ridgo from beak 
to margin ; liinge-line straight; surface, with sulci parallel to margin. 
13. S. Tumida. (Tumid Sanguinolaria.) Transversely elongated ; diagonally gibbous; hinge-line straight; surface imbricated. 
14. s. Maxima. (Large Sanguinolaria.) Transversely elongated, sub-quadrate; beaks near short, square, anterior side; hinge and basal 
lines parallel; surface, with many, concentric sulci and strife. 
15. S. Vetusta. (Ancient Sanguinolaria.) Oblong-ovate ; anteriorly short, narrowed ; with strong, concentric lines of growth. 
16. S. Arcuata. (Arcuated Sanguinolaria.) Transversely elongated; anterior side short, attenuated ; hinge-line arcuated; surface smooth. 
17. Saxicava Rugosa. (Rugged Saxicava.) Transversely oblong-ovate; beaks small, obtuse; posterior side sub-truncated - surface with 
rugged, concentric wrinkles. ’ * 
18. S. Elliptica. (Elliptical Sanguinolaria.) Elliptical, equilateral; hinge-lino straight; sides rounded; beaks obtuse; surface, with con¬ 
centric strife. 
19. S. Plicata. (Plaited Sanguinolaria .) Transversely elongated, compressed; posteriorly sub-truncated; beaks near anterior side, with 
faint ridge to margin ; hinge-line straight, with oblique sulcus below*; surface, with many, transverse plaits parallel to margin. 
20. s. Compressa. (Compressed Sanguinolaria.) Transversely oblong-ovate, compressed; anterior side, with rounded truncation ; surface 
smoothish ; with several, obscure rays from beaks to margins ; posterior side truncated; shell thin. 
22. Crassatella Plicata. (Plaited Crassatella.) Oblong-ovate; anterior side, defined by oblique, obtuse ridge; surface, with many, trans¬ 
verse plaits; margin crenated internally. 
23, 24, 25. Pandora Margaritacea. (Pearly Pandora.) Transversely oblong, arcuated; one valve flat, the other convex; beaks near 
rounded, anterior side; surface smooth, pearly. 
26, 27. Agina Purpura. ( Purple Agina.) Transversely oval; posterior side truncated; beaks prominent; surface, with transverse strife. 
Length, J in.; breadth, £ in. 
23. s. Elegans. (Elegant Sanguinolaria.) Elliptical; posterior side sub-truncated; hinge-line straight; beaks obtuse; surface, with many, 
transverse sulci from anterior side, ending where diagonal sides pass from beak to margin. 
29. s. Gibbosa. (Gibbous Sanguinolaria.) Transversely elongated, gibbose, smooth; sides gaping, rounded; beaks obtuse; surface smooth. 
30. Anatina Undulata. (Waved Anatina.) Transversely elongated; thin, convex; sub-truncated posteriorly; surface, with transverse 
undulations; pearlaceous within. | 
31. C. Sulcata. (Furrowed Crassatella.) Ovate, transversely elongated; anterior side produced, truncated ; surface, with transverse ribs and 
deep sulci; beaks pointed ; internal edgo crenated. 
32. Montaeuta Glabpa. (Smooth Mbntacuta.) Elliptical, convex, smooth, thin; posterior side sub-truncated; with one broad, primary 
tooth in each valve ; with a central hiatus. 
33. s. Transversa. (Transverse Sanguinolaria.) Transversely elongated, compressed, short; beaks near, rounded, short anterior side; 
posterior side truncated, with diagonal ridge from beaks to margins; hinge-line straight; surface, with concentric sulci, becoming angular, when 
passing over ridge. 
34. 35. Tellimya Suborbieularis. (Sub-orbicular Tellimya.) Sub-orbicular, convex, thin; beaks central, inflected ; sides equal, rounded ; 
basal margin straight, with one tooth in valve under beak, locking into double, incurved one in the other; with laminated tooth behind umbo in 
each valve. 
36. C. Compressa. (Compressed Crassatella.) Sub-triangular; anterior side short, rounded; posterior side truncated; with diagonal ridge, 
ending in acute angle ; surface, with many, transverse sulci. 
37. Sphenia Swainsoni. (Swainson's Sphenia.) Transversely oblong-oval, cuneiform; anteriorly rounded, short; posteriorly truncated; 
with horizontal, inflected, concave tooth; surface smooth. 
38. S. Parvula. (Small Sanguinolaria.) Transversely oblong-oval, compressed, smooth; with a few lines of growth; posterior side sub¬ 
truncated ; beaks central, obtuse. Length, J in.; breadth, J in. 
39. 40. Potomomya Plana. (Plain Potomomya.) Ovate, depressed, equilateral; anterior side elongated, slightly truncated ; front rounded; 
beaks depressed, obtuse; surface smooth, polished internally. 
41. S. Suleata. (Furrowed Sanguinolaria.) Transverselyeiongated; anteriorly short, narrowed; beaks obtuse; hinge-line curved, hollow; 
surface transversely furrowed; with a few, longitudinal striz*. 
42. Corbula Cardioid.es. (Cardium-like Corbula.) Transversely ovate, inflated; anterior side large, rounded; beaks large, produced, 
incurved; surface smooth, with regular lines of growth. 
43. S. Oblong’a. (Oblong Sanguinolaria.) Transversely sub-quadrate; beaks rounded, close to short, anterior side; hinge and basal lines 
parallel; surface, with concentric sulci and strife.' 
44. 45. S. Binghami. (. Bingham's ; Sphenia.} Transversely oblong-ovate; posterior side truncated; beaks prominent; surface smooth. 
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