PLATE LXXXII. 
1. Cardium Gibberulum. ( Inflated Cardium.) Sub-triangular, inflated; anteriorly rounded; posteriorly sub-truncated; sur¬ 
face smooth, crossed by remote, equidistant lines of growth. 
2. C. Turgidum. ( Swollen Gardium.) Gibbose, obovate, smooth; anterior side truncated, with twenty to thirty, longitudinal 
sulci and fine stri®; margins bluntly dentated. 
3. C. Hillanum. (Hills Cardium.) Circular; gibbose; with longitudinal sulci; surface, with many, concentric stri®. 
4,16. C. Edule. ( Edible Gardium.) Gibbose; with twenty-four to twenty-six, rounded, longitudinal ribs, crossed by transverse 
scale-like protuberances, separated by very narrow sulci. 
5. C. Ineertum. (Doubtful Gardium.) Transverse; anterior side short, rounded; posterior side large, rounded, concave above; 
beaks protruding; surface smooth. 
6, 7. C. Nitens. ( Shining Gardium.) Round; anterior side produced; smooth, shining; surface, with faint, punctated linos of 
growth; with longitudinal stri® near the base. 
8. C. Angnstatum. (Narrowed Gardium.) Transversely elongated; thin, depressed; anterior side truncated; posterior sido 
rounded; surface, with twenty-seven, longitudinal ribs ; margin dentated. 
9. C. Semi-striatum. (Semi-striated Gardium.) Elongated; sub-triangular; inflated; anterior sido short, curved; posterior 
side concave; surface, with lower portion of valves longitudinally striated; base arcuated. 
10. Pleurorhynchus Longipennis. (Long-winged Pleurorhynchus.) Transversely elongated; hinge-line straight; body del- 
toidal, with fine, radiating stri®, crossed by irregular, thin lines of growth; centre of valves with prominent, keel-shaped projection; 
with rings of smooth, long, wing-shaped processes; posterior side, with a few, faint, transverse ribs at its point. Length, f- in.; 
breadth, 1 in. 
11. P. ArmatUS. (Armed Pleurorhynchus.) Anteriorly gibbose; sub-truncate, oblique; posterior side, with elongated, slender, 
acute wing; surface, with longitudinal, divergent sulci and ribs. 
12. C. Semiglabratum. (Half-smooth Cardium .) Transversely ovate; oblique; posterior side smooth, produced below; anterior 
side with longitudinal, divergent stri®. 
13. C. Edulinum. (Small, Edible Cardium.) Thick, orbicular, convex, oblique; anterior side truncated; posterior sido pro¬ 
duced ; surface, with eighteen, rugose, longitudinal ribs. 
14,15. P. Hibernicus. (Irish Pleurorhynchus.) Deltoidal ; anterior sido produced; posterior sido truncated, in form of horse- 
hoof; bounded by large ridge, encompassing margin with a produced wing; beaks small, flat, incurved; surface, with many, 
longitudinal ridges; margins locked togethor with sharp, serrated crenulations. 
17. P. Minax. (Menacing Pleurorhynchus.) Deltoidal, transversely elongated; anteriorly gibbose; posterior side conically 
elongated; beaks anterior; surface, with many, longitudinal ribs. 
18,19. P. Trigonalis. (Trigonal Pleurorhynchus.) Elongated, horse-hoof shaped ; anteriorly gibbose, with short, smooth wing ; 
hinge-line straight; posterior side elongated, cuneiform ; surface, with many, flat longitudinal ribs. 
20. C. Citrinoideum. (Citron-like Gardium.) Oblong-ovate; beaks large; hinge-line straight; sides rounded; base arcuated; 
surface smooth, shining. 
21. C. Semigranulatum. (Semi-granulated Cardium.) Gibbose, transverse, sub-triangular; smooth, slender; posterior side 
straight, with longitudinal sulci and large granulations; surface, with longitudinal stri®; intervening ridges, with many, small, 
globose granules; margin minutely dentated. 
22. 23. C. DIssimile. (Dissimilar Cardium.) Gibbose, transversely obovate; smooth; shell thick; posterior side bounded by 
small rib and longitudinally striated; front straight. 
24, 25. P. Aliformls. (Wing-shaped Pleurorhynchus.) Sub-triangular ; anterior side convex, cordiform, with carinated, marginal 
wing; posterior sido cuneiform; beaks incurved; surface, with many, strong, longitudinal ribs. 
26. C. Lobatum. (Lobcd Cardium.) Circular, oblique; anterior side short, with central flexure; surface smooth, with a few, 
remote, indistinct lines of growth. 
27. C. Cognatum. (Kindred Cardium.) Circular; beaks central, produced, large; sides alike; surface smooth, with a few, 
remote lines of growth. 
28. C. Laevigatum. (Smooth Cardium.) Elongated, sub-oval; oblique, sub-compressed; surface, with many, flat, longitudinal 
ribs; posterior side without ribs ; internal margin crenulated. 
29. C. Elongatum. (Elongated Cardium.) Elongated, oval, oblique, inflated; with many, flat ribs and narrow sulci, crossed by 
very faint lines of growth; internal margin crenulated. 
30. C. Greenlandicum. (Greenland Gardium.) Elongated; beaks central; anteriorly curved; posteriorly concave; surface, 
with many, longitudinal ribs and narrow sulci, crossed by narrow, flat lamin®. 
31. Cardiola Fibrosa. (Fibrous Cardiola.) Cordiform; beaks acuminated, elongated; incurved; upper portion of surface 
smooth, with a few, concentric sulci; lower portion with longitudinal stri®, decussated by many, transverse stri®. 
32. C. Interrupta. (Interrupted Cardiola.) Cordiform, sub-compressed; beaks central, short; surface, with many concentric 
sulci and many longitudinal ones. 
( 101 ) 
