PLATE LXXII.* 
1. Modiola Plicata. (Plicated Modiola.) Transversely elongated; anterior side separated by a ridge, with stri «3 
above; beak, with strong, oblique plications ; rest of shell smooth, with a few, irregular lines of growth; back straight; 
anterior side truncated, posterior one obtuse. 
2. M. Bipartita. (Two-parted Modiola.) V. Plate LXXI., Figs. 22, 23. 
3. Triaxus Latus. (Broad Triaxus.) 
4. 5. Chama Squamosa. (Scaly Chama.) Sub-globose, attached by right valve, being larger than left; surface, with 
many, transverse, imbricated lamime ; posterior portion of right valve with obsolete ribs ; left valve convex ; inner surface 
smooth. 
6. M. Scalprum. (Bdl-shaped Modiola.) Transversely lengthened, curved ; beaks blunt; hinge-line elongated, bent; 
shell abruptly curbed; surface, with many, shallow lines of growth. 
7. M. Recta. (Straight Modiola.) Transversely lengthened; straight; beaks ill-defined; back straight; anterior 
side very short; posterior side lengthened; back, with oblique ribs and retroverfced wrinkles; rest of surface smoothish, 
with shallow lines of growth. 
8. M. Antiqua. (Ancient Modiola.) Obliquely ovate, convex, smooth, with a few, faint, concentric wrinkles ; 
anterior lobe indistinct ; beaks small. Length, f in. ; breadth, £ in. 
9. Trigonia Pennata. (Winged Trigonia.) Obliquely oblong, arcuated; anterior side arched, with ten to twelve 
elevated, curved, striated ribs, with smooth, intercostal spaces; posterior side flattened, concave, divided into two lobes 
by longitudinal sulcus, with a series of tuberculated ribs ; beaks sub-acute, bent; basal line cleft. 
10. 11. Caprina Lonsdalii. (LonsdaVs Caprina.) Inequivalve, larger one in form of elongated cone, flattened, 
curved twice round; smaller one, with oblique, conical umbo ; surface squamose. 
12. Trigonellites Antiquatus. (Antiquated Trigonellites.) Transversely oblong-ovate; anterior side short, rounded • 
posterior side long, rounded, with deep sulcus behind the beaks to the margin ; beneath this a shallow sulcus; back arcuated, 
with many, transverse sulci; rest of shell, with concentric, narrow sulci, crossed by radiations. 
13. T. Elongata. (Elongated Trigonia.) Elongated, sub-triangular, oblique, gibbose; beaks reflected; anterior side 
arcuated, with transverse, smooth ribs; posterior side separated by longitudinal, curved sulcus and crenulated rib, and two, 
extra, distant ribs; intercostal spaces, with wide-set, curved stri®, crossed by waved, transverse striee. 
14. T. Duplicate. (Tico-plaited Trigonia.) Transversely oblong; compressed; anterior side large, with small 
arcuated ridges; with strong, tuberculated rib separating it from posterior side ; posterior side, with oblique, transverse 
sulci; beaks large, prominent; basal margin crenated. 
15. T. Striata. (Striated Trigonia.) Elongated, sub-triangular, inflated ; posterior side, with large, crenated, trans¬ 
verse ribs ; anterior side, with many, waved strice, divided by longitudinal sulcus; basal line waved ; beaks acute; beneath 
them longitudinal, lanceolate lunule. 
16. T. PolitUS. (Polished Trigonellites.) Transverselyeiongated; anterior side short; beaks obtuse; posterior side 
lengthened, with wide, longitudinal sulcus; margin cleft; surface smooth, with minute, shallow lines of growth; back 
straight; base curved. 
17. M. Semisulcata. (Semi-furrowed Modiola.) Transversely ovate, convex, sub-bilobate ; beaks prominent; surface, 
with transverse, concentric sulci. Length, 1 in.; breadth, 2 in. 
18. Unio HlimatUS. (Buried TJnio.) Oblong-ovate, inflated ; umbones large, produced, inflected ; anterior side 
rounded ; posterior side sub-acute ; hinge-line parallel; basal margin arcuated ; surface, with concentric wrinkles. 
19. Alasmodon Vetustus. (Ancient Alas'modon.) Transversely elongated, compressed ; umbones obtuse, depressed ; 
anterior side short, sub-acute; posterior side long, broad; hinge and basal lines arcuated; surface, with broadish, concentric 
wrinkles. 
( 90 ) 
