PLATE LXXXIII. 
1. Pullastra Virginea. ( Virgin Pullastra.) Oblong-ovate, sub-corupressed; smooth, shining; with wide-set, concentric strim ; 
lunule lanceolate; margins smooth. 
2. P. Peregrina. ( Marsh Pullastra.) V. Plate LXXIV., Fig. 5. 
3,4. P. Parallela. (Parallel Pullastra.) Transversely ovate, with sub-parallel sides; beaks small, pointed; lunette lanceolate, 
deep; surface, with delicate, concentric sulci. 
5. P. Oblita. (Forgotten Pullastra.) Transversely oblong-ovate; anterior side rounded; posterior side acuminated; beaks 
obtuse; surface, with regular lines of growth. 
6. P. Decussata. (Decussated Pullastra.) Trausverse, inequilateral, sub-rliomboidal; anterior side truncated; surface, with 
longitudinal and transverse strife, producing beautiful decussation; beaks obtuse, with lanceolate lunule. 
7. P. Laevis. (Smooth Pullastra.) Transversely elongated, convex, smooth, plain; beaks minute; posterior side large, sub- 
truncated. Length, f in.; breadth, 1£ in. 
8. P. Complanata. (Smooth Pullastra.) Transversely elongated, compressed, smooth; anterior side rounded, short; beaks 
obtuse. Length, § in.; breadth. 1 \ in. 
9. Venus Elliptiea. (Elliptical Fences.) Elliptical, compressed; posterior side narrowed; anterior sido rounded; surface, with 
broad, concentric sulci, 
10. V. Antiqua. (Ancient Venus) Transversely oblong-ovate; convex; anterior side rounded; posterior side truncated; beaks 
almost undeveloped ; surface, with regular, concentric strife. 
11. P. Recondita. (Bidden Pullastra.) Transversely ovate; extremities rounded; with central ridge from |beak to margin ; 
surface, with many, concentric sulci; beaks small. 
12. P. Elliptiea. (Elliptical Pullastra.) Ovate, compressed; beaks hardly protruding; surface smooth, with wide-set, con¬ 
centric strife. 
13. P. Ipus. (Stone Pullastra.) Transversely sub-ovate; surface, with concentric, membranaceous ridges, reflected upwards; 
interstices, with longitudinal strife. 
14. V. Ovata. (Ovate Venus.) Sub-triangular, oblique, sub-compressed; beaks central, inflexed; sides equal; surface, with 
strong, longitudinal ribs, crossed by transverse strife. 
15. V. Fasciata. (Banded Venus.) Sub-triangular, sub-compressed; beaks central, acute; lunette shallow, ovate ; with longi¬ 
tudinal strife; cartilage side flat, with lanceolate depression; surface, with flat, reflected ribs. 
16. Psammobia Rigida. (Rigid Psammobia.) Transversely elongated; anterior side attenuated; posterior side truucated; 
beaks obtuse; base straight; surface, with ten to twelve, transverse ribs, and three divergent ribs from beaks towards base. 
17. Anomia Semistriata. (Semi-striated Anomia.) V. Plate LYL, Fig. 23. 
18. Avicula Decepta. (Deceptive Avicula.) Obliquely transverse; liinge-line straight; auricles undefined ; umbones obsolete; 
surface, with transverse wrinkles. 
19. 20. A. Media. (Medium Avicula.) Ovate, compressed; auricles large, unequal; hinge-line lengthened, parallel; surface 
smooth. 
21, 22. Megalodon Carinatus. (Keeled Megahdon.) Transversely elongated, oblique; sub-lobate anteriorly; surface diagonally 
carinated and olevated; beaks recurved; lunule deep ; surface, with oblique lines of growth. 
23. Venepicardia Planicosta. (Flat-ribbed Venericardia.) Cordiform, smoothisk ; with about twenty, flat, curved, longitudinal 
ribs and narrow sulci; with a few, large, crenulations on posterior margiu; beaks incurved ; shell very thick, heavy; hinge powerful. 
24. V. ScalaPis. (Ladder Venericardia.) Elongated, straight, sub-triangular, compressed; beaks obtuse, central; cardinal 
teeth long, thin ; surface, with about twenty, straight ribs, crossed by concentric strife ; internal margin denticulated. 
25. V. Tenuicosta. (Thin-ribbed Venericardia.) Orbicular or quadrangular, convex, cordiform; surface, with man}', longitu¬ 
dinal ribs, crossed by strong strim; lunette oblong, hollow; internal margin crenulated. 
26. V. Obionga. (Oblong Venericardia.) Transversely oblong, sub-quadrangular, gibbons; sides unequal; surface, with eleveu 
to thirteen, tuberoulated, distant ribs; internal margin with large crenulations. 
27. V. Orbicularis. (Orbicular Venericardia.) Orbicular, convex; surface, with sixteen, crenulated, longitudinal ribs; inter¬ 
vening sulci with concentric strim; hinge small. 
28. Cyrena Cycladiformis. (Gyclas-formed Gyrena.) Ovate; anterior side rounded; posterior side acuminated; surface smooth. 
29. V. Chamseformis. (Chama-formed Venericardia.) Oblong, convex; acuminated towards beaks; beaks curved, produced, 
with about twenty, flat, straight ribs, crossed by fine, concentric striae ; internal margin denticulated. 
30. 31. V. Globosa. (Globular Venericardia.) Globular; beaks large, obtuse ; surface, with fifteen to twenty, carinated, curved 
ribs, the carime having compressed tubercles ; inner margin denticulated. 
32. V. Acuticosta. (Sharp-ribbed Venericardia.) Transversely oblong, gibbose; beaks large, obtuse; lunette obsolete; surface, 
with about twenty, curved, carinated ribs; iuternal margins denticulated. 
33. V. Senilis. (Aged Venericardia.) Obliquely cordiform, convex; hinge strong; surface, with sixteen to eighteen, sub-imbri¬ 
cated ribs; lunette obsolete ; shell thick; internal margin crenulated. 
34. V. Deltoidea. (Deltoidal Venericardia.) Deltoidal, oblique; hinge strong; surface, with about twenty, carinated, longi¬ 
tudinal ribs; lunette small, obsolete; internal margin crenated. 
35,36. Myoeoncha Cpassa. (Thick Myoconcha.) Elongated, convex; curved and pointed at beaks; surface smooth, with a 
few, concentric lines of growth ; shell thick, valves shallow. 
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