PLATE LXI. 
1, 6, 7. Gryphsea Dilatata. ( Extended Gryphcea.) Orbicular, obscurely lobed, upper valve 
compressed, flat; umbo obtuse; under valve hemispherical, with large, incurved umbo. 
2, G. Globosa. ( Globular Gryphcea.) Obliquely sub-globose, thin, smooth; beak truncated; 
upper valve concave; hinge-line straight; anterior lobe conspicuous. 
3, 4. G. Nana. ( Dwarf Gryphcea.) Oblong-ovate, inflated; surface rugged; umbo pointed, 
obliquely incurved; variable; hinge-pit narrow, curved. 
5. G. Gigantea. ( Gigantic Gryphcea.) Orbicular; upper valve thin, concave; lower valve 
convex, with small, incurved umbo; hinge small; surface smooth, with imbricated laminne; anterior 
lobe separated by small sinus in edge of lamina?. 
8, 9. G. Vesiculosa. ( Bladder Gryphcea.) Sub-rhomboidal, oblong, deep; smaller valve con¬ 
cave, curved; beaks pointed ; hinge small; lobe distinct; sui’face smooth. 
10, 11, 12. G. Minuta. ( Minute Gryphcea.) Orbicular, thin; gibbose; beak spiral; lobe 
obscure; much compressed. 
13, 14. G. Phillipsii. ( Phillips' Gryphcea.) Longitudinal, incurved; beaks largish; both valves 
inflated. 
15. G. Columba. ( Pigeon Gryphcea.) Ovate, rounded; beaks central, attenuated; surface 
smooth; upper valve striated near hinge, somewhat quadrangular; undulated; posterior margin 
thick, flattened; opposite valve obtusely carinated. 
16, 17. G. Obliquata. ( Oblique Gryphcea.) Obliquely oblong-ovate; involute; with obscure 
lobe on right side ; smaller valve ovate, externally concave ; beak pointing to right side. 
18. G. Canalieulata. ( Ganalled Gryphcea.) Oblong-oval, depressed, transversely and concen¬ 
trically sulcated; deeper valve, with wing-shaped, canaliculated appendage and umbo curved towards 
wing; beak of opposite valve short. 
19. G. Depressa. {Depressed Gryphcea.) Ovate, oblique ; beaks obtuse ; margins and surface 
smooth, with distinct lines of growth; flat yalve plain. 
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