PLATE LXXXVIII. 
I, 2. Pullastra Peregrina. (Marsh Pullastra.) V. Plate LXXIY., Fig. B. 
3,4. Cardinia Cuneata. ( Wedge-shaped Cardinia.) Sub-triangular, cuneiform; beaks acute, with deep, 
cordiform lunule beneath; anterior side short, rounded ; surface, with many, equidistant, transverse sulci. 
5, 6. Unio Modiolaris. (Modiola-shaped Unio.) Transversely elongated, convex; anterior side short, 
narrow; beaks obtuse; hinge-line straight; back straight; base curved ; surface smooth. 
7. U. Littoralis. (Shore Unio.) Oblong-ovate, inflated; anterior side very short; beaks obtuse; back 
arcuated ; basal line concave ; surface, with faint, shallow lines of growth. 
8. U. Pietorum. ( Painter's Unio.) V. Plate LXXIV.*, Figs. 1, 2. 
9. 10. U. Urii. ( Ure's Unio.) Transversely elongated, convex; hinge-line straight; beaks depressed ; 
anterior side short; back and basal lines straight, parallel; surface, with rough, transverse undulations. 
II, 12. C. Ovalis. (Oral Cardinia.) Elliptical, transverse; beaks obtuse, approximate; lunule small, 
narrow; anterior side rounded ; back and basal lines arcuated ; external sm'face, with irregular, concentric lines 
of growth. 
13, 14. C. Scutula. (Scuttle-shaped Cardinia.) Transversely elongated, compressed; beaks obtuse, approxi¬ 
mate ; hinge-line curved; lunule long, narrow ; anterior side short, rounded; back and base arcuated; surface 
smooth, with equidistant lines of growth. 
15. U. Centralis. ( Central-beaked Unio.) Oval; anterior side short; beaks obtuse, central; basal line 
arcuated. 
16. U. Robustus. (Strong Unio.) Sub-conic, convex ; beaks central, obtuse; anterior side large, rounded ; 
basal line convex; surface, with strong lines of growth. 
17. U. Dolobratus. (Squared Unio.) Sub-quadrate, flat; anterior side very short; hinge-line curved; base 
oblique; surface uneven. 
18,19. C. Laneeolata. (Spear-shaped Cardinia.) Lanceolate, thick, transverse; anterior side short, rounded; 
hinge-line straight; beaks obtuse ; lunule small, narrow ; back and basal line arcuated ; external surface, with 
concentric lines of growth. 
20. C. Attenuata. (Attenuated Cardinia.) Cuneiform, transverse; posterior side elongated, attenuated ; 
beaks acute; lunule small, deep ; basal line arcuated. 
21,22. U. Phaseolus. (Phaseolus Unio.) Transversely elongated ; anterior side short, pointed ; beaks obtuse; 
back straight; base concave in centre. 
23. U. Aquilinus. (Eagle' s-heah Unio.) Transversely oblong-ovate; beaks minute; anterior side short, 
with small, terminal projection ; liinge-line curved; back and base convex ; surface, with transverse ridges. 
24. U. Discrepans. (Discrepant Unio.) Transversely oblong-ovate, inflated; beaks obtuse; liinge-line 
curved ; posterior side elongated, sub-truncated; back and basal line arcuated. 
25. 27. U. Austieei. (Austice's Unio.) Transversely elongated, sub-quadrate, convex; hinge-line curved; 
beaks obtuse, rounded, approximate ; anterior side truncated, short; beaks curved ; basal line straight; surface, 
with concentric wrinkles and very faint, longitudinal stride. 
26. U. Parallelus. (Parallel Unio.) Transversely elongated, sub-quadrate, flattened; beaks terminal; 
posterior side, back, and basal line straight, parallel; surface, with well-marked, concentric lines of growth. 
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