PLATE LVI.* 
1. Terebratula Spinosa. (Spinous Terebratula ♦) Sub-triangular; beaks obtuse; sides rounded; with broad, 
ongitudinal ribs, with obtuse spines. 
2, 3, 4, 5, 6, 7. T. Pleurodon. ( Side-toothed Terebratula.) V. Plate LVI., Fig. 57. 
8. T. Obliqua. (Oblique Terebratula.) Sub-compressed, transversely obovate; beak produced, incurved; with about 
fifteen angular plaits; on one side five, central one elevated. 
9,12. T. Sulcirostris. ( Furrow-beaked Terebratula.) Rhomboideo-deltoidal; beaks developed; central area, with 
five to nine divergent sulci, and intermediate ribs; ribs on sides flat; edge sharp. 
10,11. T. LatiCOSta. ( Broad-ribbed Terebratula.) Transversely elliptical; beaks small, produced, angulated, with 
minute perforation; front with mesial sinus ; with about twenty obtuse ribs, crossed by distinct lines of growth. 
13. T. Nuciformis. ( Nut-shaped Terebratula .) Transversely elongated; globose; front elevated; beak produced ; 
with thirty regular narrow ribs, with edges plain, rounded. 
14. T. Mantiae. ( Mant's Terebratula.) Sub-compressed ; sub-trigonal; beak prominent, incurved; front rounded; 
with about sixteen angular plaits ; upper valve convex. 
15. T. Lacunosa. Transversely elliptical, with projecting sinus; with many divergent ribs; beak of larger valve 
incurved; beaks obtuse. 
17, 18, 19. T. Imbricata. (Imbricated Terebratula.) V. Plate LV., Fig. 89. 
22, 23. T. Dimidiata. (Divided Terebratula.) Transversely obovate, sub-compressed; beak straight, produced; 
upper valve convex; with about thirty plaits. 
24, 25. T. Serrata. {Serrated Terebratula.) Sub-orbicular, sub-triangular, inflated; margin obtuse; beak small, 
incurved, with large concave space on each side beneath it; with about eleven sharp plaits. 
28, 29. T. Stricklandii. ( Strickland's Terebratula.) Transversely obovate, ventricose; beaks small, adpressed, 
pointed; with longitudinal canal; with about thirty sharp plaits. Length and breadth, 1 in. 
30. T. Lateralis. (Broad Terebratula.) Semi-ovate, gibbose; beak elevated, curved; front with three deep plaits, 
forming three deep angular notches, filled by sharp teeth in opposite valve; each side with two plaits; perforated valve 
flatter than the other. 
31,32. T. Crebricosta. (Many-plaited Terebratula.) Transversely obovate, sub-cylindrical, depressed; beak small, 
acute; with about thirty plaits. Length, £ in.; breadth, * in. 
33. T. Ambligonia. ( Obtuse-angled Terebratula.) Pentahedral, oblong, convex; umbone produced, with mesial 
sulcus; with five large divergent ribs on each side. 
36, 37, 38. T. Striatllla. ( Finer-striated Terebratula.) Longitudinally oblong-ovate, compressed; beak large, with 
circular aperture ; front truncated, sometimes with sinus ; with many granulated stria*. 
39. Crania Antiquior. (Ancient Crania.) Orbicular, compressed; umbo large, extended, straight. 
40. Pecten Flemingii. (Fleming's Pecten.) Convex, with many undulating ribs ; base and sides crossed by many 
irregular lines of growth and stria*. 
41. 42, 43, 44, 45. Hipponyx Cornucopiae. (Jlorn of Plenty Hipponyx .) Lower valve a depressed cone, with vortex 
nearly central, crossed by rugose lines of growth; upper valve conical; surface with many rugose lines of growth, with 
many longitudinal striae. 
46, 47, 48, 49, 50, 51. H. Laevis. (Smooth Hipponyx.) Lower valve nearly flat; upper valve oblique, conical; surface 
smooth, with a few regular lines of growth. 
52, 53. Calceola Sandalina. (Sandal-shaped Calceola.) Equilateral, inequivalve, triangular; hinge-margin trans¬ 
versely straight, notched ; upper edge arcuated ; upper valve semi-orbicular. 
54. Orbicula Punctata. (Punctured Orbicula.) Lenticular, compressed; apex sub-marginal; surface with fine 
granulations. Diameter, ^ in. — 
55, 56. C. Parisiensis. (Parisian Crania.) V. Plate LIII., Figs. 1, 2, 3, 4. 
57, 58. 0. Rugata. (Bough Orbicula.) Orbicular; upper valve a much depressed cone; surface concentrically 
wrinkled ; lower valve nearly flat. Diameter, | in.; height, £ in. 
59. C. Ovalis. (Oval Crania.) Oval; centre of superior valve conical; vertex curved; with many divergent sulci 
and intermediate ribs ; margin plain. 
60. C. Striata. (Striated Crania.) Orbicular; upper valve conical; with about fifteen strong sulci; intermediate 
ribs rounded ; interior strongly marked. 
61. 62. 0. Striata. (Striated Orbicula.) Orbicular, very convex; apex deflected, marginal, with minute radiating 
strioe. Diameter, \ in.; height, ^ in. 
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