PLATE LXXIY. 
1. Unio Aduncus. ( Crooked Unio.) Cuneiform, inflated, thick; umbones rounded; anterior slope long, straight, 
sub-truncated, concave. 
2,3. U. Walterii. (Walters Unio.) Compressed, square; anterior slope rounded; posterior slope eared; surface 
smooth, with a few, transverse wrinkles; with central, longitudinal dep ression. 
4. Cardinia Concinna. (Neat Gardinia .) Transversely oblong-ovate; beaks small, pointed, close ; hinge-line curved; 
anterior side short, narrowed; .posterior rounded; surface smooth, with transverse, sharp wrinkles ; cardinal teeth small ; 
lateral tooth large, long; back and base curved; muscular impressions deep. 
5. Pullastra Peregrina. (Marsh Pullastra.) Ovate ; beaks obtuse, remote ; hinge-line oblique; anterior side short; 
extremities rounded; basal line arcuated; surface smooth, with a few, well-marked furrows. 
6. U. SubtruncatllS. (Sub-truncated Unio.) Ovate, compressed; edges of valves obtuse ; posterior side cuneiform; 
beaks small, remote. 
'• U. Martini. (Martin's Unio.) Convex; beaks produced, central; posterior side large, rounded; anterior side 
acute; surface smooth. 
C. Crassissima. (Very Thick Gardinia,) Ovate, very thick; beaks incurved, acute; hinge-line arcuated, with 
triangular, cardinal tooth and broad, long, lateral tooth in each valve; anterior side short, rounded ; beak convex; base 
straight; surface, with transverse lines of growth ; muscular impressions deep. 
A- C. Abducta. (Distant Cardinia.) Sub-trigonal, inflated; beaks small, close; lunule cordate; surface smooth, with 
a few, faint, transverse lines of growth. 
10. u. Solandri. (Solander's Unio.) Transversely oblong-ovate, compressed, thin; hinge-line straight; umbones 
rugose, minute, close; anterior slope sub-truncated; basal line hollow; surface smooth, with indistinct, transverse 
pearlaceous undulations. Thickness, £ in. 
11. U. Compressus. (Compressed Unio.) Ovate, compressed ; umbones central, produced; hinge-line arcuated. 
12. U. AntiqilUS. (Ancient Unio.) Elongated, transversely ovate; beaks produced, sub-compressed; posterior side 
short, rounded; anterior side elongated, sub-acute ; hinge-line straight; surface smooth. 
13. U. AcutllS. (Acute Unio.) Transversely elongated; anterior side short, rounded; posterior side elongated, 
acuminated, rounded; hinge-line straight; beaks incurved, close; surface smooth, with a few, concentric wrinkles. 
14. U. POPPectUS. (Extended Unio.) Sub-compressed, elongated; anterior side elongated, sub-tnincated, pointed • 
hinge-line straight; surface convex, smooth. 
15,17. U. SubconstPictllS. (Sub-constricted Unio.) Oblong-ovate; beaks sub-central, incurved, close; posterior side 
lengthened; anterior side rounded; hinge-line sub-triangular, with sub-constriction from beaks to margin; basal line 
arcuated; surface smooth, with some concentric sulci. 
16. U. Mantelli. (MantclVs Unio.) Oblong-ovate, compressed; dorsal and basal margins parallel, straight; posterior 
side short; beaks produced ; surface smooth. 
18. C. Cpassiuscula. (Thickened Gardinia.) Elliptical, sub-compressed ; valves thick; beaks depressed, with fine, 
incurved points; hinge-line undulous, thickened; muscular impressions deep; pallial impressions well-defined; back and 
base arcuated; surface smooth, with a few, remote lines of growth. 
ID. C. HybPida. (Mongrel Gardinia.) Cuneiform, sub-triangular; hinge-line curved; beaks close ; lunule elongated, 
lanceolate, deeply impi’essed; anterior side concave below beaks; posterior side arcuated from beaks to base; surface 
smooth, with transverse, deep sulci. 
20. C. ListePi. (Lister's Gardinia.) Cardiform, cuneiform, thick; beaks recurved, acute, central; lunule deep, but 
small; back rounded; base, with flexure; surface, with sub-imbricated ridges. 
21. U. COPdifOPmiS. (Heart-shaped Unio.) Heart-shaped; posterior side rounded; anterior side pointed; beaks 
rounded, large, produced. 
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